BMWG Aamer Akhter
Internet Draft Cisco Systems
Intended status: Informational
Expires: October 21, 2009 Rajiv Asati
Cisco Systems
Carlos Pignataro
Cisco Systems
April 21, 2009
MPLS Forwarding Benchmarking Methodology for IP Flows
draft-ietf-bmwg-mpls-forwarding-meth-03.txt
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Abstract
This document describes a methodology specific to the benchmarking
of Multi-Protocol Label Switching (MPLS) forwarding devices, limited
to the most common MPLS packet forwarding scenarios and delay
measurements for each, considering IP flows. It builds upon the
tenets set forth in RFC2544, RFC1242 and other IETF Benchmarking
Methodology Working Group (BMWG) efforts. This document seeks to
extend these efforts to the MPLS paradigm.
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Table of Contents
1. Introduction...................................................3
2. Document Scope.................................................4
3. Key Words to Reflect Requirements..............................5
4. Test Methodology...............................................5
4.1. Test Considerations..........................................6
4.1.1. Abbreviations Used.........................................6
4.1.2. IGP Support................................................7
4.1.3. Label Distribution Support.................................7
4.1.4. Frame Formats..............................................8
4.1.5. Frame Sizes...............................................10
4.1.6. Time-to-Live (TTL) or Hop Limit...........................13
4.1.7. Trial Duration............................................13
4.1.8. Traffic Verification......................................14
4.1.9. Address Resolution and Dynamic Protocol State.............14
5. Reporting Format..............................................15
6. MPLS Forwarding Benchmarking Tests............................16
6.1. Throughput..................................................18
6.1.1. Throughput for MPLS Label Imposition......................18
6.1.2. Throughput for MPLS Label Swap............................19
6.1.3. Throughput for MPLS Label Disposition (Unlabeled).........20
6.1.4. Throughput for MPLS Label Disposition (Aggregate).........21
6.1.5. Throughput for MPLS Label Disposition (PHP)...............22
6.2. Latency Measurement.........................................23
6.3. Frame Loss Rate Measurement (FLR)...........................24
6.4. System Recovery.............................................25
6.5. Reset.......................................................26
7. Security Considerations.......................................27
8. IANA Considerations...........................................27
9. Acknowledgement...............................................27
10. References...................................................28
10.1. Normative References.......................................28
10.2. Informative References.....................................28
Author's Addresses...............................................29
1. Introduction
Over the past several years, there has been an increase in the use
of MPLS as a forwarding architecture in new and existing network
designs. MPLS, defined in [RFC3031], is a foundation technology and
basis for many advanced technologies such as Layer 3 MPLS-VPNs,
Layer 2 MPLS-VPNs, and MPLS Traffic-Engineering.
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However, there is no standard method defined to compare and contrast
the foundational MPLS packet forwarding capabilities of network
devices. This document proposes a methodology using common criteria
(such as throughput, latency, frame loss rate, system recovery,
reset etc.) to evaluate MPLS forwarding of any implementation.
2. Document Scope
The benchmarking methodology principles outlined in RFC2544
[RFC2544] are independent of forwarding techniques, however, they
don't fully address MPLS benchmarking. The fact that MPLS forwarding
places a different burden on the resources of the network forwarding
devices from that of IP forwarding, MPLS forwarding benchmarking
specifics are desired.
The purpose of this document is to describe a methodology specific
to the benchmarking of MPLS forwarding devices. The methods
described are limited in scope to the most common MPLS packet
forwarding scenarios and corresponding performance measurements in a
laboratory setting. It builds upon the tenets set forth in RFC2544
[RFC2544], RFC1242 [RFC1242] and other IETF Benchmarking Methodology
Working Group (BMWG) efforts. In other words, this document is not a
replacement for, but a complement to, RFC 2544.
This document focuses on the MPLS label stack [RFC3032] having only
one entry, as it is the fundamental of MPLS forwarding. It is
expected that future documents may cover the benchmarking of MPLS
applications such as L3VPN [RFC4364], L2VPN [RFC4664], Fast ReRoute
[RFC4090] etc., which require more than one entry in the MPLS label
stack.
Moreover, to address the majority of current deployments' needs,
this document focuses on having IP packets as the MPLS payload. In
other words, label distribution for IP Forwarding Equivalence Class
(FEC)[RFC3031] is prescribed (see Section 4.1.2) by this document.
It is expected that future documents may focus on having non-IP
packets as the MPLS payload.
Note that the presence of an MPLS label stack does not require the
length of MPLS payload (which is an IP packet, per this document) to
be changed, hence, the effective maximum size of a frame can
increase by Z bytes (where Z = 4 x number of label stack entries),
as observed in current deployments. This document focuses on
benchmarking such a scenario.
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3. Key Words to Reflect Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119
[RFC2119]. RFC 2119 defines the use of these key words to help make
the intent of standards track documents as clear as possible. While
this document uses these keywords, this document is not a standards
track document.
4. Test Methodology
The set of methodologies described in this document will use the
topology described in this section. An effort has been made to
exclude superfluous equipment needs such that each test can be
carried out with a minimal number of devices.Figure 1 illustrates
the sample topology in which the Device Under Test (DUT) is
connected to the test ports on the test tool in accord with the Fig
1 of RFC2544 -
+-----------------+
+---------+ | | +---------+
| Test | | | | Test |
| Port A1 +-----+ DA1 DB1 -----+ Port B1 |
+---------+ | | +---------+
+---------+ | DUT | +---------+
| Test | | | | Test |
| Port A2 +-----+ DA2 DB2 +-----+ Port B2 |
+---------+ | | +---------+
... | | ...
+---------+ | | +---------+
| Test | +-----------------+ | Test |
| Port Ap | | Port Bp |
+---------+ +---------+
Figure 1 Topology for MPLS Forwarding Benchmarking
A represents a Tx-side Module of the test tool, whereas B represents
an Rx-side Module of the same test tool. Of course, the suffixed
numbers (1, 2...p) represent ports on a Module.
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Similarly, DA represents an Rx-side Module of the DUT, whereas DB
represents Tx-side Module. The suffixed numbers (1, 2...p) represent
ports on a Module.
p = number of {DA, DB} pair ports on DUT. It is determined by the
maximum unidirectional forwarding throughput of the DUT and the load
capacity of the port media (e.g. interface) connecting the DUT to
the test tool.
For example, if the DUT's maximum forwarding throughput is 100
frames per second (fps), and the load capacity of the port media
(e.g. interface) is 50 fps, then p => 2 is needed to sufficiently
test the maximum frame forwarding.
The exact throughput is a measured quantity obtained through
testing. Throughput may vary depending on the number of ports used,
and other factors. The number of ports (p) used SHOULD be reported.
Please see Test Setup in Section 6, and recommended to follow Fig 1
from S6 of RFC2544.
4.1. Test Considerations
This methodology assumes a full-duplex uniform medium topology. The
medium used MUST be reported in each test result. Issues regarding
mixed transmission media, speed mismatches, media header differences
etc, are not under consideration. Traffic affecting features such as
Flow control, QoS, Graceful Restart etc. MUST be disabled, unless
explicitly requested in the test case. Additionally, any non-
essential traffic MUST also be avoided.
4.1.1. Abbreviations Used
The terms used in this document remain consistent with those defined
in "Benchmarking Terminology for Network Interconnect Devices"
RFC1242 [RFC1242]. This terminology SHOULD be consulted before using
or applying the recommendations of this document.
Please refer to Figure 1 for a topology view of the network. The
following abbreviations are used in this document -
M := Module on a device (i.e. Line-Card or Slot; could be A or B)
p := Port number (i.e. Port on the Module; could be 1, 2 etc.)
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RN := Remote Network (i.e. network that is reachable via a port of a
module; could be B1RN1 or B2RN5 to mean the first network reachable
via port 1 of module B e.g. B1, or the 5th network reachable via
port 2 of module B, etc.). RN is considered to be the FEC from MPLS
perpsective.
4.1.2. IGP Support
It is highly RECOMMENDED that all of the ports (A1, DA1, DB1, and
A2) on DUT and test tool support a dynamic Interior Gateway Protocol
(IGP) for routing such as IS-IS, OSPF, EIGRP, RIP etc. Furthermore,
there are testing considerations in this document that the device be
able to provide a stable control-plane during heavy forwarding
workloads. This is to ensure that control plane instability during
load conditions is not the contributing factor towards frame
forwarding performance.
The route distribution method (OSPF, IS-IS, EIGRP, RIP, Static
etc.), if used, MUST be reported. Furthermore, if any specific
configuration is used to maintain control-plane stability during the
test (i.e. Control Plane Protection, Control Plane Rate Limiting,
etc.), then it MUST also be reported.
4.1.3. Label Distribution Support
The DUT and test tool must support at least one protocol for
exchanging MPLS label/FEC bindings for Prefix Forwarding Equivalence
Class (FEC) [RFC3031]. The DUT and test tool MUST be capable of
learning and advertising MPLS label/FEC bindings via the chosen
protocol(s), and use them during packet forwarding all the time
(including when the label/FEC bindings change). The most commonly
used protocols are Label Distribution Protocol (LDP) [RFC5036],
Resource Reservation Protocol-Traffic Engineering (RSVP-TE)
[RFC3209] and Border Gateway Protocol (BGP) [RFC3107].
All of the ports (A1, DA1, DB1, B1 etc.) either on the DUT or the
test tool used in the testing SHOULD support LDP, RSVP-TE, and BGP
for IPv4 or IPv6 Prefix Forwarding Equivalence Classes (FECs).
This document does NOT recommend the use of static label to
establish the MPLS label switched paths (LSPs), unless specified
explicitly by the testcase. This is because the use of static label
is quite uncommon in the production networks.
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4.1.4. Frame Formats
This section explains the frame formats for IP and MPLS packets
(Section 4.1.4.1), the usage of IP as the mandatory layer 3 protocol
and as the MPLS packet payload (Section 4.1.4.2), change in frame
format during forwarding (Section 4.1.4.3) and recommended frame
formats for the MPLS benchmarking (Section 4.1.4.4).
4.1.4.1. Frame format for IP vs. MPLS
A test frame carrying an IP packet is illustrated in the figure 1
below. Note that RFC2544 [RFC2544] prescribes using such a frame as
the test frame over the chosen layer 2 media.
+------------------------------------------------+
| Layer 2 | Layer 3 = IP | Layer 4 = UDP |
+------------------------------------------------+
Figure 1 Frame Format for IP packet
Unlike a test frame carrying an IP packet, a test frame carrying an
MPLS packet contains an 'MPLS label stack' [RFC3032] immediately
after the layer 2 header (and before the IP header, if any) as
illustrated in figure 2 below -
+--------------------------------------------------------+
| Layer 2 | MPLS | Layer 3 = IP | Layer 4 = UDP |
+--------------------------------------------------------+
Figure 2 Frame format for MPLS packet
The MPLS label stack is represented as a sequence of "label stack
entries", where each label stack entry is 4 bytes, as illustrated in
figure 1 of [RFC3032]. This document requires only a single entry in
the MPLS label stack in an MPLS packet.
MPLS label values used in any testcase MUST be outside the reserved
label value (0-15) unless stated otherwise.
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4.1.4.2. MPLS packet payload
This document prescribes using IP packet as the MPLS payload (as
illustrated in figure 2 above). Generically speaking, this document
mandates the test frame to include IP (either IPv4 or IPv6) as the
layer 3 protocol, in accord with Section 8 of [RFC2544] and
independent of the MPLS label stack presence, for three reasons:
1) This enables using IP Prefix Forwarding Equivalence Class (FEC)
[RFC3031], which is a must for every MPLS network.
2) This provides the foundation or baseline for benchmarking of
various other MPLS applications such as L3VPN, L2VPN, TE-FRR etc.
3) This enables leveraging RFC2544 [RFC2544], which prescribes using
IP packet with UDP data as the test frames. (Note that [RFC5180]
also uses this prescription for IPv6 benchmarking).
While the usage of non-IP payloads is possible, it requires an MPLS
application e.g. L2VPN, whose benchmarking may be covered in
separate BMWG documents (MPLS L2VPN Benchmarking, for example) in
the future. This is also explained in Section 2.
4.1.4.3. Change in Frame Format due to MPLS Imposition and Disposition
A frame carrying IP or MPLS packet may go through any of the three
MPLS forwarding operations: label imposition (or LSP Ingress), label
swap and label disposition (or LSP Egress), as defined in [RFC3031].
It is important to understand the change of the frame format from IP
to MPLS or vice versa depending on the forwarding operation.
In label imposition (or LSP ingress) operation, the DUT receives a
frame containing an IP packet and forwards a frame containing an
MPLS packet if the corresponding forwarding lookup for the IP
destination points to a label imposition operation.
In label swap operation, the DUT receives a frame containing an MPLS
packet and forwards a frame containing an MPLS packet if the
corresponding forwarding lookup for the label value points to a
label swap operation.
In label disposition (or LSP egress) operation, the DUT receives a
frame containing an MPLS packet and forwards a frame containing an
IP packet if the corresponding forwarding lookup for the label value
points to a label disposition operation.
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4.1.4.4. Frame Formats to be used for Benchmarking
This document prescribes using two test frame formats to
appropriately test the forwarding operations: (1) Frame format for
IP and (2) Frame format for MPLS. Both formats are explained in
Section 4.1.3.1. Additionally, the format of the test frame may
change depending on the forwarding operation.
1. For testcases involving label imposition operation - the test
tool must use the frame format for IP packet (figure 1) to send
the test frames to the DUT, and must use the frame format for MPLS
packet (figure 2) to receive the test frames from the DUT.
2. For testcases involving label swap operation - the test tool must
use the frame format for MPLS packet (figure 2) to send the test
frames to the DUT, and must use the frame format for MPLS packet
(figure 2) to receive the test frames from the DUT.
3. For testcases involving label disposition operation - the test
tool must use the frame format for MPLS packet (figure 2) to send
the test frames to the DUT, and must use the frame format for IP
packet (figure 1) to receive the test frames from the DUT.
4.1.5. Frame Sizes
Two types of port media are commonly deployed: Ethernet and POS
(Packet Over Synchronous Optical Network). This section identifies
the frame sizes that SHOULD be used for each media type, if
supported by the DUT. Section 4.1.4.1 covers Ethernet and 4.1.4.2
covers POS.
First, it is important to note the possible increase in frame size
due to the presence of an MPLS label stack in the frame (as
explained in the Section 4.1.3).
As observed in the current deployments, presence of an MPLS label
stack in a layer 2 frame is assumed to be transparent to layer3=IP,
which continues to follow the conventional maximum frame payload
size [RFC3032] (1500 bytes for ethernet, say). This means that the
effective maximum frame payload size [RFC3032] of the resulting
layer2 frame is Z bytes more than the conventional maximum frame
payload size, where Z = 4 x number of entries in the label stack.
Hence, to ensure successful delivery of layer2 frames carrying MPLS
packets and realistic benchmarking, it is recommended to set the
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media MTU value to the effective maximum frame payload size
[RFC3032], which equals Z bytes + conventional maximum frame payload
size. It is expected that such a change in media MTU value only
impacts the effective Maximum Frame Payload Size for MPLS packets,
but not for IP packets.
Note that this document requires only a single entry in the MPLS
label stack in an MPLS packet. In other words, the depth of the
label stack is set to one e.g. Z = 4 x 1 = 4 bytes.
Furthermore, in accord with Section 9 and 9.1 of RFC2544, this
document prescribes that each testcase case is run with different
(layer 2) frame sizes in different trials. Additionally, results MAY
also be collected with multiple simultaneous frame sizes (sometimes
referred to as an IMIX to simulate real network traffic according to
the frame size ordering and usage). There is no standard for
mixtures of frame sizes, and the results are subject to wide
interpretation. See Section 18 of RFC 2544. When running trials
using multiple simultaneous frame sizes, the DUT configuration MUST
remain the same.
4.1.5.1. Frame Sizes to be used on Ethernet Media
Ethernet media, in all its types, has become the most commonly
deployed port media in MPLS networks. If any test case execution
(such as Label Imposition case) requires the testtool to send (or
receive) a layer2 frame containing an IP packet, then the following
frame sizes SHOULD be used for benchmarking over ethernet media:
64, 128, 256, 512, 1024, 1280 and 1518 bytes. This is in line with
Section 9 and 9.1 of RFC2544. Figure 1 illustrates the header sizes
for an untagged ethernet frame containing an IP payload (per
RFC2544) -
<----------------64-1518B------------------------>
<--18B---><-----------46-1500B------------------->
+------------------------------------------------+
| Layer 2 | Layer 3 | Layer 4 (and higher) |
+------------------------------------------------+
Figure 3 Frame Size for Label Imposition cases
Note: The 64 and 1518 byte frame size represents the minimum and
maximum length of an untagged Ethernet frame, as per IEEE 802.3
[IEE8023]. A frame size commonly used in operational environments
may range from 68 to 1522 bytes, which are the minimum and maximum
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length of a single VLAN-tagged frame, as per IEEE 802.1D
[IEE8021].
Note: While jumbo frames are outside the scope of the 802.3 IEEE
standard, tests SHOULD be executed with the frame sizes that are
supported by the DUT. Examples of commonly used jumbo (ethernet)
frame sizes are: 4096, 8192, and 9216 bytes.
If any test case execution (such as Label Swap and Label Disposition
cases) requires the testtool to transmit (or receive) a layer2 frame
containing an MPLS packet, then the untagged layer2 frame must
include an additional 4 bytes for the MPLS header, resulting in the
following frame sizes to be used for benchmarking over ethernet
media: 68, 132, 260, 516, 1028, 1284 and 1522 bytes. Figure 2
illustrates the header sizes for an untagged ethernet frame
containing an MPLS packet -
<------------------68-1522B------------------------------>
<--18B---><--4B--><-----------46-1500B------------------->
+--------------------------------------------------------+
| Layer 2 | MPLS | Layer 3 | Layer 4 (and higher) |
+--------------------------------------------------------+
Figure 4 Frame Size for Label Swap and Disposition cases.
Note: The Media MTU on the link between the testtool and DUT must
be changed, if needed, to accommodate the effective maximum frame
payload size [RFC3032] resulting from adding an MPLS label stack
to the IP packet. As clarified in Section 3.1 of RFC3032, most
layer 2 media drivers are capable of sending and receiving layer 2
frames with effective maximum frame payload size. Many vendors
also allow the Media MTU to be changed for MPLS, without changing
it for IP. The recommended link MTU value for MPLS is Z bytes more
than the conventional maximum frame payload size [RFC3032] (for
example, the conventional maximum frame payload size for ethernet
is 1500 bytes). This document prescribes Z=4 bytes. If a vendor
DUT doesn't allow such an MTU change, then the benchmarking can
not be performed for the true maximum frame payload size [RFC3032]
and this must be reported.
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4.1.5.2. Frame Sizes to be used on POS Media
Packet over SONET (POS) media are commonly used for edge uplinks and
high-bandwidth core links. POS may use one of various
encapsulations techniques (such as PPP, HDLC, Frame Relay etc.),
resulting in the layer 2 header (~4 bytes) being less than that of
ethernet media. The rest of the frame format (illustrated in figure
2 and 3) remains pretty much unchanged.
If the MPLS forwarding characterization of POS interfaces on the DUT
is desired, then the following frame sizes SHOULD be used:
Label Imposition testcases: 47, 64, 128, 256, 512, 1024, 1280,
1518, 2048 and 4096 bytes.
Label Swap and Dispoisition testcases: 51, 68, 132, 260, 516,
1028, 1284, 1522, 2052 and 4100 bytes.
4.1.6. Time-to-Live (TTL) or Hop Limit
The TTL value in the frame header must be large enough to allow a
TTL decrement to happen and still be forwared through the DUT. The
TTL field may either be MPLS TTL, IPV4 TTL, or IPV6 Hop Limit
depending on the exact forwarding scenario under evaluation.
If TTL/Hop Limit Decrement, as specified in [RFC3443], is a
configurable option on the DUT, the setting SHOULD be reported.
4.1.7. Trial Duration
Unless otherwise specified, the test portion of each trial SHOULD be
no less than 30 seconds when static routing is in place, and no less
than 200 seconds when a dynamic routing protocol and LDP (default
LDP holddown timer is 180 seconds) are being used. If the holddown
timer default vaue is changed, then it should be reported and the
trial duration should still be 20 seconds more than the holddown
timer value.
The longer trial time used for dynamic routing protocols is to
verify that the DUT is able to maintain a stable control plane when
the data-forwarding plane is under stress.
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4.1.8. Traffic Verification
In all cases, sent traffic MUST be accounted for, whether it was
received on the wrong port, correct port or not received at all.
Specifically, traffic loss (also referred to as frame loss) is
defined as the traffic (i.e. one or more frames) not received where
expected (i.e. received on incorrect port, or received with
incorrect layer2 or above header information etc.). In addition, the
presence or absence of MPLS label stack, every field value inside
the label stack, if present, ethertype (0x8847 or 0x8848 vs.
0x0800), frame sequencing and frame check sequence (FCS), MUST be
verified in the received frame.
Many test tools may, by default, only verify that they have received
the embedded signature on the receive side. However, for MPLS header
presence verification, some tests will require the MPLS header to be
imposed while others will require a swap or disposition. Hence, this
document requires the test tool to verify the MPLS stack depth. An
even greater level of verification would be to check if the correct
label was imposed, but that is out of scope for these tests.
4.1.9. Address Resolution and Dynamic Protocol State
If a test setup utilizes any dynamic protocols for control plane
signalling (eg. ARP, PPP (including MPLSCP), OSPF, LDP, etc.), then
all state for the protocols MUST be pre-established bofore the test
case is executed (i.e. packet streams are started).
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5. Reporting Format
For each test case, it is RECOMMENDED that the following variables
be reported in addition to the specific parameters requested by the
test case:
Parameter Units or Examples
Prefix Forwarding IPv4, IPv6, Both
Equivalence Class (FEC)
Label Distribution Protocol LDP, RSVP-TE, BGP (or
combinations)
MPLS Forwarding Operation Imposition, Swap,
Disposition
IGP ISIS, OSPF, EIGRP, RIP,
static.
Throughput Frames per second and
Bits per second
Port Media GigE, POS, ATM etc.
Port Speed 1 gbps, 100 Mbps, etc.
Interface Encapsulation Ethernet, Ethernet VLAN,
PPP, HDLC etc.
Frame Size [See Section Bytes
4.1.3]
p (Number of {DA, DB} pair 1,2, etc.
ports per Figure 1)
The individual test cases may have additional reporting requirements
that may refer to other RFCs.
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6. MPLS Forwarding Benchmarking Tests
MPLS is a different forwarding paradigm from IP. Unlike IP packet
and IP forwarding, an MPLS packet may contain more than one MPLS
header and may go through one of three forwarding operations -
imposition (or LSP ingress), swap or disposition (or LSP egress), as
defined in [RFC3031]. Such characteristics desire further
granularity in MPLS forwarding benchmarking than those described in
RFC2544. Thus the benchmarking may include, but not limited to:
1. Throughput
2. Latency
3. Frame Loss rate
4. System Recovery
5. Reset
6. MPLS TC (previously known as EXP [RFC5462]) field Operations
(including explicit-null cases)
7. Negative Scenarios (TTL expiry, etc)
8. Multicast
However, this document focuses only on the first five categories,
inline with the spirit of RFC2544. All the benchmarking test cases
described in this document are expected to, at a minimum, follow the
'Test Setup' and 'Test Procedure' below -
Test Setup
Referring to Figure 1, a single port (p = 1) on both A and B
Modules SHOULD be used. However, if the forwarding throughput of
the DUT is more than that of the media rate of a single port, then
additional ports on A and B Modules MUST be enabled so as to
exceed the DUT's forwarding throughput. In such a case, the
procedures described in Section 16 of RFC2544 must be followed to
accommodate the multi-port scenario. The frame formats transmitted
and received must be in accord with Section 4.1.4.3 and 4.1.4.4,
and frame sizes must be in accord with in Section 4.1.5.
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Note - The test tool must be configured to not advertise a prefix
or FEC to the DUT on more than one port. In other words, the DUT
must associate a FEC with one and only one DB port. The Equal Cost
Multi-Path (ECMP) behavior in MPLS networks uses heuristics
[RFC4928], hence, the usage of ECMP is NOT permitted by this
document to ensure the deterministic forwarding behavior during
the benchmarking.
Test Procedure
In accord with Section 26 of RFC2544 [RFC2544], the traffic is
sent from test tool port(s) Ap to the DUT at a constant load for a
fixed time interval, and is received from the DUT on test tool
port(s) Bp. The frame may contain either an IP packet or an MPLS
packet depending on the testcase need, as described in the Section
4.1.4.3. Furthermore, the IP packet must be either an IPv4 or IPv6
packet, depending on whether the MPLS benchmarking is done for
IPv4 or IPv6.
If any frame loss is detected, then a new iteration is needed
where the offered load is decreased and the sender will transmit
again. An iterative search algorithm MUST be used to determine the
maximum offered frame rate with a zero frame loss.
This maximum offered frame rate that results in zero frame loss
through the DUT is defined as the Throughput in Section 3.17 of
[RFC1242] for that test case. Informally, this rate is referred to
as the No Drop Rate.
Each iteration should involve varying the offered load of the
traffic, while keeping the other parameters (test duration, number
of ports, number of addresses, frame size etc) constant, until the
maximum rate at which none of the offered frames are dropped is
determined.
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6.1. Throughput
This Section contains the description of the tests that are related
to the characterization of DUT's MPLS traffic forwarding.
6.1.1. Throughput for MPLS Label Imposition
Objective
To obtain the DUT's Throughput (as per RFC 2544) during label
imposition or LSP Ingress forwarding operation (i.e. IP to MPLS).
Test Setup
In addition to the test setup described in Section 6, the test
tool must advertise the IP prefix(es) i.e. RNx (using a routing
protocol as per Section 4.1.2) and associated MPLS label-FEC
binding(s) (using a label distribution protocol as per Section
4.1.3) on its receive ports Bp to DUT. The test tool may learn the
IP prefix(es) on it's transmit ports Ap from DUT.
MPLS and/or label distribution protocol must be enabled only on
the test tool receive ports Bp and DUT transmit ports DBp.
Discussion
The DUT's MPLS forwarding table (also referred to as FEC-to-NHLFE
(FTN) mapping table per [RFC3031]) must contain a non-reserved
MPLS label value as the outgoing label for each learned IP prefix
corresponding to the label-FEC binding, resulting in DUT
performing the IP-to-MPLS forwarding operation. The test tool must
receive MPLS packets on receive ports Bp (from DUT) with the same
label values that were advertised.
Procedure
Please see Test Procedure in Section 6. Additionally, the test
tool MUST send the frames containing IP packets (with IP
destination belonging to the advertised IP prefix(es)) on transmit
ports Ap, and expect to receive frames containing MPLS packets on
receive ports Bp, as described in Section 4.1.4.4.
Reporting Format
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The result should be reported as per Section 5 and as per RFC2544.
Results for each test SHOULD be in the form of a table with a row
for each of the tested frame sizes. Additional columns SHOULD
include: offered load and measured throughput.
6.1.2. Throughput for MPLS Label Swap
Objective
To obtain the DUT's Throughput (as per RFC 2544) during label
swapping operation (i.e. MPLS to MPLS).
Test Setup
In addition to setup described in Section 6, the test tool must
advertise IP prefix(es) (using a routing protocol as per Section
4.1.2) and associated MPLS label-FEC bindings (using a label
distribution protocol as per Section 4.1.3) on the receive ports
Bp, and then learn the IP prefix(es) as well as the label-FEC
binding(s) on the transmit ports Ap. The test tool must use the
learned MPLS label values and learned IP prefix values in the
frames transmitted on ports Ap to DUT.
MPLS and/or label distribution protocol must be enabled on the
test tool ports Bp and Ap, and DUT ports DBp and DAp.
Discussion
The DUT's MPLS forwarding table (also referred to as FEC-to-NHLFE
(FTN) mapping table per [RFC3031]) must contain non-reserved MPLS
label values as the outgoing and incoming labels for the learned
IP prefixes, resulting in MPLS-to-MPLS forwarding operation e.g.
label swap. The test tool must receive MPLS packets on receive
ports Bp (from DUT) with the same label values that were
advertised using the label distribution protocol. The received
frames must contain the same number of MPLS headers as those of
transmitted frames.
Procedure
Please see Test Procedure in Section 6. Additionally, the test
tool must send frames containing MPLS packets (with IP destination
belonging to the advertised IP prefix(es)) on it's transmit ports
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Ap, and expect to receive frames containing MPLS packets on its
receive ports Bp, as described in Section 4.1.4.4.
Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
Results for each test SHOULD be in the form of a table with a row
for each of the tested frame sizes.
6.1.3. Throughput for MPLS Label Disposition (Unlabeled)
Objective
To obtain the DUT's Throughput (as per RFC 2544) during label
disposition or LSP Egress forwaridng operation (i.e. MPLS to IP)
using "Unlabeled" outgoing label.
Test Setup
In addition to setup described in Section 6, the test tool must
advertise the IP prefix(es) (using a routing protocol as per
Section 4.1.2) without any MPLS label-FEC bindings on the receive
ports Bp, and then learn the IP prefix(es) as well as the FEC-
label binding(s) on the transmit ports Ap. The test tool must use
the learned MPLS label values and learned IP prefix values in the
frames transmitted on ports Ap.
MPLS and/or label distribution protocol must be enabled only on
the test tool port(s) Ap and DUT port(s) DAp.
Discussion
The DUT's MPLS forwarding table (also referred to as FEC-to-NHLFE
(FTN) mapping table per [RFC3031]) must contain an Unlabeled
outgoing label (also known as untagged) for the learned IP prefix,
resulting in MPLS-to-IP forwarding operation.
Procedure
Please see Test Procedure in Section 6. Additionally, the test
tool must send frames containing MPLS packets on its transmit
ports Ap (with IP destination belonging to the IP prefix(es)
advertised on port Bp), and expect to receive frames containing IP
packets on its receive ports Bp, as described in Section 4.1.4.4.
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Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
Results for each test SHOULD be in the form of a table with a row
for each of the tested frame sizes.
6.1.4. Throughput for MPLS Label Disposition (Aggregate)
Objective
To obtain the DUT's Throughput (as per RFC 2544) during label
disposition or LSP Egress forwarding operation (i.e. MPLS to IP)
using "Aggregate" outgoing label.
Test Setup
In addition to setup described in Section 6, the DUT must be
provisioned such that it allocates an aggregate outgoing label
(please see Section 3.20 in [RFC3031]) to an IP prefix, which
aggregates a set of prefixes learned on ports DBp from the test
tool. The prefix aggregation can be performed using BGP
aggregation (Section 9.2.2.2 of [RFC4271]), IGP aggregation
(Section 16.5 of [RFC2328]), etc.).
The DUT must advertise the aggregating IP prefix along with the
associated MPLS label-FEC binding on ports DAp to the test tool.
The test tool then must use the learned MPLS label values and
learned IP prefix values in frames transmitted on ports Ap to the
DUT. The test tool must receive frames containing IP packets on
ports Bp from the DUT.
MPLS and/or label distribution protocol must be enabled only on
the test tool port(s) Ap and DUT port(s) DAp.
Discussion
The DUT's MPLS forwarding table (also referred to as FEC-to-NHLFE
(FTN) mapping table per [RFC3031]) must contain an aggregate
outgoing label and IP forwarding table must contain a valid entry
for the learned prefix(es), resulting in MPLS-to-IP forwarding
operation (i.e. MPLS header removal followed by IP lookup).
Procedure
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Please see Test Procedure in Section 6. Additionally, the test
tool must send frames containing MPLS packets on its transmit
ports Ap (with IP destination belonging to the IP prefix(es)
advertised on port Bp), and expect to receive frames containing IP
packets on its receive ports Bp, as described in Section 4.1.4.4.
Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
Results for each test SHOULD be in the form of a table with a row
for each of the tested frame sizes.
6.1.5. Throughput for MPLS Label Disposition (PHP)
Objective
To obtain the DUT's Throughput (as per RFC 2544) during label
disposition (i.e. MPLS to IP) or penultimate hop popping (PHP)
using "imp-null" outgoing label.
Test Setup
In addition to setup described in Section 6, the test tool must be
set up to advertise the IP prefix(es) (using a routing protocol as
per Section 4.1.2) and associated MPLS label-FEC binding with a
reserved MPLS label value = 3 (using a label distribution protocol
as per Section 4.1.3) on its receive ports Bp. The test tool must
learn the IP prefix(es) as well as the MPLS label-FEC bindings on
its transmit ports Ap. The test tool then must use the learned
MPLS label values and learned IP prefix values in the frames
transmitted on ports Ap to DUT. The test tool must receive frames
containing IP packets on receive ports Bp (from DUT).
MPLS and/or label distribution protocol must be enabled on the
test tool ports Bp and Ap, and DUT ports DBp and DAp.
Discussion
This test case characterizes the Penultimate Hop Popping (PHP),
which is described in RFC3031.
The DUT's MPLS forwarding table (also referred to as FEC-to-
Next_Hop_Label_Forwarding_Entry (FTN) mapping table per [RFC3031])
must contain a reserved MPLS label value = 3 (e.g. pop or imp-
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null) as the outgoing label for the learned prefix(es), resulting
in MPLS-to-IP forwarding operation.
This test case characterizes DUT's penultimate hop popping (PHP)
functionality.
Procedure
Please see Test Procedure in Section 6. Additionally, the test
tool must send frames containing MPLS packets on its transmit
ports Ap (with IP destination belonging to advertised IP
prefix(es)), and expect to receive frames containing IP packets on
its receive ports Bp, as described in Section 4.1.4.4.
Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
Results for each test SHOULD be in the form of a table with a row
for each of the tested frame sizes.
6.2. Latency Measurement
This measures the time taken by the DUT to forward the MPLS packet
during various MPLS switching paths such as IP-to-MPLS or MPLS-to-
MPLS or MPLS-to-IP involving an MPLS label stack.
Objective
To obtain the average latency induced by the DUT during MPLS
packet forwarding for each of five forwarding operations.
Test Setup
Follow the Test Setup guidelines established for each of four MPLS
forwarding operations in Section 6.1.1 (for IP-to-MPLS), 6.1.2
(for MPLS-to-MPLS), 6.1.3 (for MPLS-to-IP Unlabeled), 6.1.4 (for
MPLS-to-IP Aggregate) and 6.1.5 (for MPLS-to-IP PHP) one by one.
Procedure
Please refer to Section 26.2 in RFC2544 in addition to following
the associated procedure for each MPLS forwarding operation in
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accord with the Test Setup described earlier -
IP-to-MPLS forwarding (Imposition) Section 6.1.1
MPLS-to-MPLS forwarding (Swap) Section 6.1.2
MPLS-to-IP forwarding (Disposition) Section 6.1.3
MPLS-to-IP forwarding (Aggregate) Section 6.1.4
MPLS-to-IP forwarding (PHP) Section 6.1.5
Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
6.3. Frame Loss Rate Measurement (FLR)
This measures the percentage of MPLS frames that were not forwarded
during various switching paths such as IP-to-MPLS (imposition) or
MPLS-to-IP (swap) or MPLS-IP (disposition) by the DUT under
overloaded state.
Please refer to RFC2544 Section 26.3 for more details.
Objective
To obtain the frame loss rate, as defined in RFC1242, for each of
three MPLS forwarding operations of a DUT, throughout the range of
input data rates and frame sizes.
Test Setup
Follow the Test Setup guidelines established for each of four MPLS
forwarding operations in Section 6.1.1 (for IP-to-MPLS), 6.1.2
(for MPLS-to-MPLS), 6.1.3 (for MPLS-to-IP Unlabeled), 6.1.4 (for
MPLS-to-IP Aggregate) and 6.1.5 (for MPLS-to-IP PHP) one by one.
Procedure
Please refer to Section 26.3 of RFC 2544 RFC2544 and follow the
associated procedure for each MPLS forwarding operation one-by-one
in accord with the Test Setup described earlier -
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IP-to-MPLS forwarding (Imposition) Section 6.1.1
MPLS-to-MPLS forwarding (Swap) Section 6.1.2
MPLS-to-IP forwarding (Disposition) Section 6.1.3
MPLS-to-IP forwarding (Aggregate) Section 6.1.4
MPLS-to-IP forwarding (PHP) Section 6.1.5
Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
6.4. System Recovery
Objective
To characterize the speed at which a DUT recovers from an overload
condition.
Test Setup
Follow the Test Setup guidelines established for each of four MPLS
forwarding operations in Section 6.1.1 (for IP-to-MPLS), 6.1.2
(for MPLS-to-MPLS), 6.1.3 (for MPLS-to-IP Unlabeled), 6.1.4 (for
MPLS-to-IP Aggregate) and 6.1.5 (for MPLS-to-IP PHP) one by one.
Procedure
Please refer to Section 26.5 of RFC2544 and follow the associated
procedure for each MPLS forwarding operation in the referenced
Sections one-by-one in accord with the Test Setup described
earlier -
IP-to-MPLS forwarding (Imposition) Section 6.1.1
MPLS-to-MPLS forwarding (Swap) Section 6.1.2
MPLS-to-IP forwarding (Disposition) Section 6.1.3
MPLS-to-IP forwarding (Aggregate) Section 6.1.4
MPLS-to-IP forwarding (PHP) Section 6.1.5
Reporting Format
The result should be reported as per Section 5 and as per RFC2544.
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6.5. Reset
Objective
To characterize the speed at which a DUT recovers from a device or
software reset.
Test Setup
Follow the Test Setup guidelines established for each of four MPLS
forwarding operations in Section 6.1.1 (for IP-to-MPLS), 6.1.2
(for MPLS-to-MPLS), 6.1.3 (for MPLS-to-IP Unlabeled), 6.1.4 (for
MPLS-to-IP Aggregate) and 6.1.5 (for MPLS-to-IP PHP) one by one.
For this testcase, the requirements of LDP and a routing-protocol
are removed and replaced by static configurations. For the IP-to-
MPLS iteration, static route configurations should be applied. For
the MPLS-to-MPLS and MPLS-to-IP static label configurations must
be applied.
For this test, all graceful-restart features MUST be disabled.
Procedure
Please refer to RFC2544 Section 26.5. Examples of hardware and
software resets are:
Hardware reset - forwarding module resetting (e.g. OIR).
Software reset - reset initiated through a CLI (e.g. reload).
Additionally, follow the specific Section for procedure (and test
Setup) for each MPLS forwarding operation one-by-one -
IP-to-MPLS forwarding (Imposition) Section 6.1.1
MPLS-to-MPLS forwarding (Swap) Section 6.1.2
MPLS-to-IP forwarding (Disposition) Section 6.1.3
MPLS-to-IP forwarding (Aggregate) Section 6.1.4
MPLS-to-IP forwarding (PHP) Section 6.1.5
Reporting Format
Same as RFC2544 and the parameters of Section 5 including the
specific kind of reset performed.
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7. Security Considerations
Benchmarking activities, as described in this memo, are limited to
technology characterization using controlled stimuli in a laboratory
environment, with dedicated address space and the constraints
specified in the sections above.
The benchmarking network topology will be an independent test setup
and MUST NOT be connected to devices that may forward the test
traffic into a production network or misroute traffic to the test
management network.
Furthermore, benchmarking is performed on a "black-box" basis,
relying solely on measurements observable external to the DUT/SUT.
Special capabilities SHOULD NOT exist in the DUT/SUT specifically
for benchmarking purposes. Any implications for network security
arising from the DUT/SUT SHOULD be identical in the lab and in
production networks.
There are no specific security considerations within the scope of
this document.
8. IANA Considerations
There are no considerations for IANA at this time.
9. Acknowledgement
The authors would like to thank Mo Khalid, who motivated us to write
this document. We would like to thank Rodney Dunn, Chip Popoviciu,
Jeff Byzek, Jay Karthik, Rajiv Pap, Samir Vapiwala, Silvija Andrijic
Dry, Scott Bradner, Al Morton and Bill Cerveny for their careful
review and suggestions.
This document was prepared using 2-Word-v2.0.template.dot.
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10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2544] Bradner, S. and McQuaid, J., "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544, March 1999.
[RFC1242] Bradner, S., Editor, "Benchmarking Terminology for Network
Interconnection Devices", RFC 1242, July 1991.
[RFC3031] Rosen et al., "Multiprotocol Label Switching
Architecture", RFC 3031, August 1999.
[RFC3032] Rosen et al., "MPLS Label Stack Encoding", RFC 3032,
January 2001.
[RFC3107] Rosen, E. and Rekhter, Y., "Carrying Label Information in
BGP-4", RFC 3107, May 2001.
[RFC5036] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and
B. Thomas, "LDP Specification", RFC 5036, January 2001.
10.2. Informative References
[RFC5180] Popoviciu, C., et al, "IPv6 Benchmarking Methodology for
Network Interconnect Devices", RFC 5180, May 2008.
[RFC3209] Awduche, et al., "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, Dec 2001.
[RFC4364] Rosen E. and Rekhter Y., "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC4364, February 2006.
[RFC4271] Rekhter, Y. and T. Li, "Framework for Layer 2 Virtual
Private Networks (L2VPNs)", RFC 4664, Sep 2006.
[RFC4664] Rosen, E. and Andersson L., " A Border Gateway Protocol 4
(BGP-4)", RFC 4271, Jan 2006.
[IEE8021] Mick Seaman (editor), "IEEE Std 802.1D-2004, MAC Bridges",
Feb 2004.
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[IEE8023] LAN/MAN Standards Committee of the IEEE Computer Society,
"IEEE Std 802.3as-2006, Part 3: Carrier Sense Multiple
Access with Collision Detection (CSMA/CD) Access Method
and Physical Layer Specifications, Amendment 3: Frame
format extensions", Nov 2006.
[RFC3443] Agarwal, P. and Akyol, B., "Time To Live (TTL) Processing
in MPLS Networks", RFC3443, Jan 2003.
[RFC2328] Moy, J., "OSPF Version 2", RFC2328, April 1998.
[RFC5462] Asati, R. and Andersson, L., "Multi-Protocol Label
Switching (MPLS) label stack entry: "EXP" field renamed to
"Traffic Class" field", RFC5462, Feb 2009.
[RFC4928] Swallow, et al., "Avoiding Equal Cost Multipath Treatment
in MPLS Networks", RFC4928, June 2007.
[RFC4090] Pan, et al., "Fast Reroute Extensions to RSVP-TE for LSP
Tunnels", RFC4090, May 2005.
Author's Addresses
Aamer Akhter
Cisco Systems
7025 Kit Creek Road
RTP, NC 27709
USA
Email: aakhter@cisco.com
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Rajiv Asati
Cisco Systems
7025 Kit Creek Road
RTP, NC 27709
USA
Email: rajiva@cisco.com
Carlos Pignataro
Cisco Systems
7200-12 Kit Creek Road
RTP, NC 27709
USA
Email: cpignata@cisco.com
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