BMWG G. Fioccola
Internet-Draft E. Vasilenko
Intended status: Informational P. Volpato
Expires: 25 April 2024 Huawei Technologies
L. Contreras
Telefonica
B. Decraene
Orange
23 October 2023
Benchmarking Methodology for MPLS Segment Routing
draft-vfv-bmwg-srmpls-bench-meth-08
Abstract
This document defines a methodology for benchmarking Segment Routing
(SR) performance for Segment Routing over MPLS (SR-MPLS). It builds
upon RFC 2544, RFC 5695 and RFC 8402.
Status of This Memo
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Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. SR-MPLS Forwarding . . . . . . . . . . . . . . . . . . . . . 4
3. Test Methodology . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Test Setup . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Label Distribution Support . . . . . . . . . . . . . . . 6
3.3. Frame Formats and Sizes . . . . . . . . . . . . . . . . . 7
3.4. Protocol Addresses . . . . . . . . . . . . . . . . . . . 9
3.5. Trial Duration . . . . . . . . . . . . . . . . . . . . . 9
3.6. Traffic Verification . . . . . . . . . . . . . . . . . . 10
3.7. Buffer tests . . . . . . . . . . . . . . . . . . . . . . 10
4. Reporting Format . . . . . . . . . . . . . . . . . . . . . . 11
5. SR-MPLS Forwarding Benchmarking Tests . . . . . . . . . . . . 12
5.1. Throughput . . . . . . . . . . . . . . . . . . . . . . . 14
5.1.1. Throughput for SR-MPLS PUSH . . . . . . . . . . . . . 14
5.1.2. Throughput for SR-MPLS NEXT . . . . . . . . . . . . . 14
5.1.3. Throughput for SR-MPLS CONTINUE . . . . . . . . . . . 15
5.2. Buffers size . . . . . . . . . . . . . . . . . . . . . . 15
5.3. Latency . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.4. Frame Loss . . . . . . . . . . . . . . . . . . . . . . . 16
5.5. System Recovery . . . . . . . . . . . . . . . . . . . . . 16
5.6. Reset . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
9.1. Normative References . . . . . . . . . . . . . . . . . . 17
9.2. Informative References . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
Segment Routing (SR), defined in [RFC8402], leverages the source
routing paradigm. The headend node steers a packet through an SR
Policy [RFC9256], instantiated as an ordered list of segments. A
segment, referred to by its Segment Identifier (SID), can have a
semantic local to an SR node or global within an SR domain. SR
supports per-class explicit routing while maintaining per-class state
only at the ingress nodes to the SR domain.
However, there is no standard method defined to compare and contrast
the foundational SR packet forwarding capabilities of network
devices. This document aims to extend the efforts of [RFC1242],
[RFC2544] and [RFC5695] to SR network.
The SR architecture can be instantiated on two data-plane: SR over
MPLS (SR-MPLS) and SR over IPv6 (SRv6). This document is limited to
SR-MPLS.
SR can be directly applied to the Multiprotocol Label Switching
(MPLS) architecture [RFC8660]. A segment is encoded as an MPLS
label. An SR Policy is instantiated as a stack of labels.
The MPLS label stack in scope of this document has a minimum of two
entries, e.g. two SIDs. But it is RECOMMENDED that the tests
described in the next sections can be applied to label stacks with
more than two SIDs. The reason for having a minimum of two SIDs,
hence two labels, is to simulate a SID list, e.g. to simulate the
explicit steering of a packet flow through different paths/nodes.
It is expected that future documents may cover the benchmarking of
SR-MPLS applications such as Layer 3 VPN (L3VPN) [RFC4364], EVPN
[RFC7432], Fast ReRoute [I-D.ietf-rtgwg-segment-routing-ti-lfa], etc.
SR-MPLS involves 3 types of forwarding plane operations (PUSH/ NEXT/
CONTINUE) as further described in Section 2. SR list for PUSH
operation is typically constructed by the source node with a SR
Policy, see [RFC9256].
[RFC5695] describes a methodology specific to the benchmarking of
MPLS forwarding devices, by considering the most common MPLS packet
forwarding scenarios and corresponding performance measurements.
The purpose of this document is to describe a methodology specific to
the benchmarking of Segment Routing. The methodology described is a
complement for [RFC5695].
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1.1. Requirements Language
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 RFC 2119 [RFC2119],
RFC 8174 [RFC8174].
2. SR-MPLS Forwarding
SR leverages the source routing paradigm. In MPLS, the ordered list
of segments is encoded as a stack of MPLS labels. An SR Policy is
instantiated through the MPLS Label Stack: the Segment IDs (SIDs) of
a Segment List are inserted as MPLS Labels. Hence SR-MPLS Segment
List typically contains more labels. The classical forwarding
functions available for MPLS networks allow implementing the SR
operations.
The operations applied by the SR-MPLS forwarding plane are PUSH,
NEXT, and CONTINUE.
The PUSH operation corresponds to the Label Push function, according
to the MPLS label pushing rules specified in [RFC3032]. It consists
of pushing one or more MPLS labels on top of an incoming packet then
sending it out of a particular physical or virtual interface towards
a particular next hop.
The NEXT operation corresponds to the Label Pop function, which
consists of removing the topmost label. The action before and/or
after the popping depends on the instruction associated with the
active SID on the received packet prior to the popping. It is
equivalent to Penultimate Hop Popping (PHP).
The CONTINUE operation corresponds to the Label Swap function,
according to the MPLS label-swapping rules in [RFC3031]. It consists
of associating an incoming label with an outgoing interface and
outgoing label and forwarding the packet to the outgoing interface.
It is equivalent to Ultimate Hop Popping (UHP).
The encapsulation of an IP packet into an SR-MPLS packet is performed
at the edge of an SR-MPLS domain, reusing the MPLS Forwarding
Equivalent Class (FEC) concept. A Forwarding Equivalent Class (FEC)
can be associated with an SR Policy ([RFC9256]). When pushing labels
onto a packet's label stack, the Time-to-Live (TTL) field and the
Traffic Class (TC) field of each label stack entry must also be set.
All SR nodes in the SR domain use an IGP signaling extension to
advertise their own prefix SIDs. After receiving the advertised
prefix SIDs, each SR node calculates the prefix SIDs to the
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advertisers. The prefix SID advertisement can be an absolute value
advertisement or an index value advertisement. In this regard, the
mapping of Segments to MPLS Labels (SIDs) is an important process in
the SR-MPLS data plane. Each router can advertise its own available
label space to be used for Global Segments called Segment Routing
Global Block (SRGB) and an identical range of labels (SRGB) should be
used in all routers in order to simplify services and operations. In
the SR domain Global Segments can be identified by an index, which
has to be re-mapped into a label, or by an absolute value. This is
relevant for the nodes that perform the NEXT operation to the
segments, because the label for the next segments needs to be crafted
accordingly.
[RFC9256] specifies the concepts of SR Policy and steering into an SR
Policy. The header of a packet steered in an SR Policy is augmented
with the ordered list of segments associated with that SR Policy. SR
Policy state is instantiated only on the headend node, which steers a
flow into an SR Policy. Intermediate and endpoint nodes do not
require any state to be maintained. SR Policies can be instantiated
on the headend dynamically and on demand basis. SR policy may be
installed by PCEP [RFC8664], BGP
[I-D.ietf-idr-segment-routing-te-policy], or via manual configuration
on the router. PCEP and BGP signaling of SR Policies can be the case
of a controller-based deployment.
3. Test Methodology
3.1. Test Setup
The test setup in general is compliant with section 6 of [RFC2544]
but augmented by the methodology specified in section 4 of [RFC5695]
using many interfaces. It is needed to test the packet forwarding
engine that may have different performance based on the number of
interfaces served. The Device Under Test (DUT) may have
oversubscribed interfaces, then traffic for such interfaces should be
proportionally decreased according to the specific DUT
oversubscription ratio. All interfaces served by a particular packet
forwarding engine should be loaded in reverse proportion to the
claimed oversubscription ratio. Tests SHOULD be done with
bidirectional traffic that better reflects the real environment for
SR-MPLS nodes. It is OPTIONAL to choose non-equal proportion for
upstream and downstream traffic for some specific aggregation nodes.
The RECOMMENDED topology for SR-MPLS Forwarding Benchmarking should
be the same used for MPLS benchmarking, as described in section 4 of
[RFC5695]. A simplified view is reported below for reference.
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+----------+
+---------| |<---------+
| +-------| Tester |<-------+ |
| | +-----| |<-----+ | |
| | | +----------+ | | |
| | | | | |
| | | +--------+ | | |
| | +----->| |-------+ | |
| +------->| DUT |---------+ |
+--------->| |-----------+
+--------+
Figure 1: Test environment for SR-MPLS Forwarding Benchmarking
Differently from [RFC5695], this document prefers the use of the term
"interface" instead of "port" as an interface may be either virtual
or physical.
Interface numbers involved in the tests and their oversubscription
ratio MUST be reported. SIDs represent only prefix and adjacency
segments. In general, MPLS labels at the bottom of the stack may be
used to encode services (L2/L3 VPNs) but it is out of the scope of
this document.
Segment Routing may also be implemented as a software network
function in an NFV Infrastructure and, in this case, additional
considerations should be done. [ETSI-GR-NFV-TST-007] describes test
guidelines for NFV capabilities that require interactions between the
components implementing NFV functionality.
Special capabilities SHOULD NOT exist in the DUT/SUT specifically for
benchmarking purposes.
3.2. Label Distribution Support
As specified in [RFC8402], in the context of an IGP-based distributed
control plane, two topological segments are defined: the IGP-
Adjacency segment and the IGP-Prefix segment; while, in the context
of a BGP-based distributed control plane, two topological segments
are defined: the BGP peer segment and the BGP Prefix segment.
It is RECOMMENDED that the DUT and test tool support at least one
option for SID stack construction:
* IS-IS Extensions for Segment Routing [RFC8667]
* OSPF Extensions for Segment Routing [RFC8665]
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* Segment Routing Prefix Segment Identifier Extensions for BGP
[RFC8669]
* Segment Routing Policy Architecture [RFC9256].
A routing protocol (OSPF or ISIS or BGP) SHOULD be used for the
construction of the simplest stack of 1 SID. It is RECOMMENDED that
SR policy should be used for the construction of a stack with 2 SIDs.
It is possible to test longer SID lists if there is an interest.
It is RECOMMENDED that the top SID on the list (outer label) should
be an adjacency type to emulate the traffic engineering scenario. In
all cases, SID stack configuration SHOULD happen before packet
forwarding would be started. Control plane convergence speed is not
the subject of the present tests.
The label distribution method and SR policy construction method used
MUST be reported according to Section 4.
3.3. Frame Formats and Sizes
The tests for SR-MPLS will use Frame characteristics similarly to
section 4.1.5 of [RFC5695], except the need for a bigger MTU to
accommodate many MPLS labels.
It is to be noted that [RFC5695] requires exactly a single entry in
the MPLS label stack. For the scope of this document, this is not
enough to simulate a typical SR-MPLS SID list. MPLS label values
used in any test case MUST be outside the reserved label value
(0-15). The number of entries in the label stack MUST be reported.
According to section 4.1.4.2 of [RFC5695], the payload is RECOMMENDED
to have an IP packet (IPv6 or IPv4 with UDP or TCP) to better
represent the real environment.
It is assumed that the test would be for Ethernet media only. Other
media is possible (see section 4.1.5.2 of [RFC5695] for the POS
example). Some layer 2 technologies (like POS/PPP) have bit- or
byte- stuffing then [RFC4814] may help to calculate real performance
more accurately or else 1-2% error is expected. The most popular
layer 2 technology for SR is Ethernet, it does not have stuffing.
Section 4.1.5 of [RFC5695] observes that the presence of an MPLS
label has the effect of increasing the maximum frame payload size
[RFC3032] so that "the resulting Layer 2 frame is Z octets more than
the conventional maximum frame payload size, where Z = 4 x number of
entries in the label stack".
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As already stated, the SID list in scope of this document is composed
of two SIDs. Accordingly, it is RECOMMENDED to set the media MTU
value to the effective maximum frame payload size [RFC3032], which
equals 2 * Z octets + conventional maximum frame payload size. It is
expected that such a change in the media MTU value only impacts the
effective Maximum Frame Payload Size for MPLS packets, but not for IP
packets. The depth of the label stack is set to Z = 4 x 2 = 8
octets.
The resulting Ethernet frame structure is depicted in the next
figure.
<-------------------------72-1526B-------------------------->
<---18B---><--4B--><--4B--><-----------46-1500-------------->
+---------+-------+-------+---------+-----------------------+
| | MPLS | MPLS | | | |
| Layer 2 | Label | Label | Layer 3 | Layer 4 | High layers |
+---------+-------+-------+---------+-----------------------+
Figure 2: Ethernet Frame Structure
RECOMMENDED frame sizes are presented below. Any other frame sizes
may be added if suspected of abnormal behavior. For example, some
architectures may allocate buffer memory in big fixed chunks that may
drop performance if frame sizes are chosen just a few octets more
than the fixed chunk size (the second chunk would have a very low
memory utilization).
RECOMMENDED frame sizes are the following:
* Ethernet Minimal: 64+n*4 (n=2)
* DUT Minimal Wire Speed: typically 128-256 (it depends on the DUT
specification)
* Ethernet Typical: 1518+n*4 (n=2)
* DUT Maximum: 9000 (or any claimed maximum)
where n is the number of labels (SID Depth).
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Note that n*4 octets are added in the previous calculations to
accommodate MPLS labels needed for respective tests. The typical
frame size values are listed above for the DUT minimal wire speed and
maximum, but they can be modified according to the DUT
characteristics. The minimum wire speed frame size can be considered
based on the DUT specification but, in some cases, many tests may be
needed in the search for the real minimum wire speed frame size.
VLAN tag may additionally increase the frame size. VLAN tag tests
are OPTIONAL.
3.4. Protocol Addresses
IANA reserved an IPv6 address block 2001:0002::/48 ([RFC4773]) for
use with IPv6 benchmark testing and block 198.18.0.0/15 ([RFC3330])
for IPv4 benchmark testing. The type of infrastructure protocol
(IPv6 vs IPv4) that should be used for IGP and BGP in the tests
should be chosen according to the test purpose and requirements.
As it is discussed in section 3.1, there is a need to load the whole
forwarding engine (on all interfaces). [RFC4814] discusses the
importance to have many flows with address randomization for
acceptable hash-based load balancing that is implemented in all
forwarding engines. In the context of this document, it may also be
relevant for SIDs, because SIDs may be used for hash to choose the
next link (depending on DUT default or desired configuration). It is
important to check what exactly is used for the hash load balancing
algorithm on the DUT to keep these numbers sufficiently random and at
volume. It is very often that IP addresses and transport protocol
ports are used instead of SIDs.
3.5. Trial Duration
The test portion of each trial must take into account the respective
protocol configuration. IGP protocols typically have a shorter hold
time, while some BGP default configurations may be up to 180 seconds.
It is needed to check the default hold time of the DUT for the
respective protocol used.
In general, the test portion of each trial SHOULD be no less than 250
seconds, which is a reasonable value based on common hold time
values. But a test can also adapt to the real setup and select a
different value if default configuration has been changed. The test
portion of each trial can be chosen at least 10 seconds longer than
the hold time to verify that the DUT can maintain a stable control
plane when the data-forwarding plane is under stress.
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3.6. Traffic Verification
Traffic verification is following section 10 of [RFC2544] and section
4.1.8 of [RFC5695].
As stated in section 10 of [RFC2544], "the test equipment SHOULD
discard any frames received during a test run that are not actual
forwarded test frames. For example, keep-alive and routing update
frames SHOULD NOT be included in the count of received frames. In
all cases, sent traffic MUST be accounted for, whether it was
received on the wrong interface, the correct interface, or not
received at all. In all cases, the test equipment SHOULD verify the
length of the received frames and check that they match the expected
length.
Preferably, the test equipment SHOULD include sequence numbers (or
signature) in the transmitted frames and check for these numbers on
the received frames. If this is done, the reported results SHOULD
include in addition to the number of frames dropped, the number of
frames that were received out of order, the number of duplicate
frames received and the number of gaps in the received frame
numbering sequence".
Many test tools may, by default, only verify that they have received
the embedded signature on the receive side. However, some SR-MPLS
tests assumes headers modifications. All packets SHOULD be checked
of the correct headers values on the receiving side.
In addition, section 4.1.8 of [RFC5695] requires that "the presence
or absence of the MPLS label stack, every field value inside the
label stack, if present, ethertype (0x8847 or 0x8848 versus 0x0800 or
0x86DD), frame sequencing, and frame check sequence (FCS) MUST be
verified in the received frame". This "to verify that the packets
received by the test tool carry the expected MPLS label".
3.7. Buffer tests
Back-to-back frame test was initially discussed in section 26.4
[RFC2544] and later improved in [RFC9004] which is considered the
comprehensive reference for back-to-back frame test. Modern
forwarding engines are typically flexible in the buffer distribution
between different interfaces. Hence, like for all other benchmarking
tests, it is important to stress the forwarding engine on all
interfaces. It should be necessary to perform throughput tests first
because only frame sizes that stress DUT below wire-speed can be used
for back-to-back tests. Buffers would be filled with the rate equal
to the difference between the theoretical maximum frame rate (wire-
speed) and DUT measured throughput for the respective frame size.
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The test time could be much shorter than recommended in [RFC9004]
because typical SR DUT is hardware-based with claimed buffers between
30ms to 100ms. It is better to consult with the vendor to find a
good starting search point. If DUT is software-based then [RFC9004]
recommendation for 2-30 seconds is applied.
Queuing SHOULD NOT have weighted random early detection (WRED) or any
other mechanism that may start dropping packets before the buffer is
filled. Queuing SHOULD be configured for the tail drop which is,
typically, a non-default configuration. Back-to-back frame test is
rather complex and expensive (50 runs for every frame size). Hence,
it is OPTIONAL for SR-MPLS.
4. Reporting Format
There are a few parameters that need to be changed in section 5 of
[RFC5695] for SR MPLS tests.
Reporting parameter preserved from [RFC5695]:
* Throughput in bytes per second and frames per second
* Frame sizes in Octets (see Section 3.3)
* Interface speed (10/50/100/400/800/etc GE)
* Interface encapsulation (Ethernet or Ethernet VLAN)
* Interface media type (probably Ethernet)
Parameters changed from [RFC5695]:
* SR-MPLS Forwarding Operations (PUSH/ NEXT/ CONTINUE).
* Label Distribution protocol and IGP are the same in the context of
SR-MPLS. Hence, it is called "label distribution".
New parameters that MUST be reported are:
* Interface numbers involved for ingress and egress in the tests and
their respective oversubscription ratio.
* Upstream/downstream traffic proportion (equal bidirectional or
some other split).
* Number of Segments considered in the MPLS Label Stack and the type
of SIDs used (Global/Local).
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* SR Policy construction method (PCEP, BGP, manual configuration).
* Type of the payload (IPv6/IPv4, UDP/TCP).
* Time to recover from the overload state
* Time to recover from the reset state and reset type (particular
module in reset)
* Tested buffers size in frames with respective frame size (for the
optional back-to-back test); it is possible to record calculated
buffer time for wire-speed throughput in milliseconds.
Some parameters may be the same for all tests (like Media type or
Ethernet encapsulation) then it may be reported one time.
5. SR-MPLS Forwarding Benchmarking Tests
In general, tests are compliant with [RFC2544] but the important
correction discussed in section 6 of [RFC5695] is applied: interfaces
chosen for every test MUST stress all interfaces served by one
forwarding engine. It is better to check the DUT specification for
the relationship between interfaces and the forwarding engine to
minimize the number of interfaces involved. But it is possible to
understand the worst case by looking at the throughput and latency
from the trial tests. If any doubt exists about how full is the
offered load for the forwarding engine then it is better to stress
all interfaces of the line card or all interfaces for the whole
router with a centralized forwarding engine. A partial load on the
forwarding engine would show optimistic results. Controllable
traffic distribution between many interfaces (as specified in section
4 of [RFC5695]) would need separate SID announcements for separate
interfaces.
The performance of modern packet forwarding engines may be huge that
may need to involve many testers to sufficiently load the DUT as
presented on figure 3. Then results correlation and recalculation of
the real performance would be an additional burden.
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+----------+
+-------| Tester1 |<-------+
| +-----| |<-----+ |
| | +----------+ | |
| | | |
| | +--------+ | |
| +----->| |-------+ |
+------->| DUT |---------+
+------->| |---------+
| +----->| |-------+ |
| | +--------+ | |
| | | |
| | +----------+ | |
| +-----| Tester2 |<-----+ |
+-------| |<-------+
+----------+
Figure 3: Many testers
As specified in section 6 of [RFC5695], the traffic is sent from test
tool Tx interface(s) to the DUT at a constant load for a fixed-time
interval, and is received from the DUT on test tool Rx interface(s).
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 (No-Drop Rate - NDR). Each
iteration should involve varying the offered load of the traffic,
while keeping the other parameters (test duration, number of
interfaces, number of addresses, frame size, etc.) constant, until
the maximum rate at which none of the offered frames are dropped is
determined.
The test can be repeated with a varying number of Segments pushed on
ingress in order to measure the resulting maximum number. It can
also be tested the maximum number of Segments that are correctly
load-balanced in transit by only changing the Nth label in the stack
and detect when load-balancing fails.
Therefore, the two main parameters that can be evaluated are:
Maximum offered frame rate,
Maximum number of Segments that can be pushed and hashed by the SR
node for load-balancing.
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5.1. Throughput
This section contains a description of the tests that are related to
the characterization of a DUT's SR-MPLS traffic forwarding
throughput.
The list of segments for SR-MPLS is represented as a stack of MPLS
labels. There are three distinct operations to be tested: PUSH, NEXT
and CONTINUE. These correspond to the three forwarding operations of
an MPLS packet: PUSH (or LSP Ingress), POP (or LSP Egress), or SWAP.
It is separately discussed only for throughput tests as an example.
5.1.1. Throughput for SR-MPLS PUSH
Objective: To obtain the DUT's Throughput during the PUSH forwarding
operation. It is similar to label Push or LSP Ingress forwarding
operation, as per section 6.1.1 of [RFC5695] and section 26.1 of
[RFC2544].
Procedure: Similar to [RFC5695] extended to test SID list longer than
1 SID (more than 2 are RECOMMENDED). SID list can be from 1 to N
SIDs. N could be specified a priori or measured as part of the test.
The test tool must advertise and learn the IP prefix(es) and SIDs on
respective sides, as per Section 3.4, and must use one option for SID
stack construction, as per Section 3.2, on its receive and transmit
interfaces towards the DUT.
Reporting Format: A table with all parameters specified in Section 4.
5.1.2. Throughput for SR-MPLS NEXT
Objective: To obtain the DUT's Throughput during the NEXT forwarding
operation. It is equivalent to MPLS Label Pop or Penultimate Hop
Popping (PHP), as per section 6.1.3 of [RFC5695] and section 26.1 of
[RFC2544].
Procedure: Similar to [RFC5695] extended to test SID list longer than
1 SID (more than 2 are RECOMMENDED). SID list can be from 1 to N
SIDs. N could be specified a priori or measured as part of the test.
The test tool must advertise and learn the IP prefix(es) and SIDs on
respective sides, as per Section 3.4, and must use one option for SID
stack construction, as per Section 3.2, on its receive and transmit
interfaces towards the DUT.
Reporting Format: A table with all parameters specified in Section 4.
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5.1.3. Throughput for SR-MPLS CONTINUE
Objective: To obtain the DUT's Throughput during the CONTINUE
forwarding operation. It is equivalent to MPLS Label Swap or
Ultimate Hop Popping (UHP), as per section 6.1.2 of [RFC5695] and
section 26.1 of [RFC2544]. Non-reserved MPLS label values MUST be
used.
Procedure: Similar to [RFC5695] extended to test SID list longer than
1 SID (more than 2 are RECOMMENDED). SID list can be from 1 to N
SIDs. N could be specified a priori or measured as part of the test.
The test tool must advertise and learn the IP prefix(es) and SIDs on
respective sides, as per Section 3.4, and must use one option for SID
stack construction, as per Section 3.2, on its receive and transmit
interfaces towards the DUT.
Reporting Format: A table with all parameters specified in Section 4.
5.2. Buffers size
Back-to-back frame test is OPTIONAL and SHOULD be performed only
after throughput tests because it SHOULD use only frame sizes that
DUT is not capable to forward wire-speed, as explained in
Section 3.7.
Objective: To determine the buffer size as defined in section 6 of
[RFC9004] for each of the SR-MPLS forwarding operations.
Procedure: Should be inherited from [RFC9004] with 2 SIDs RECOMMENDED
(many SIDs are possible). Despite the simple general idea for
filling the buffer until tail drop, [RFC9004] has many details for
procedure, precautions, and calculations that would be too lengthy to
copy here.
Reporting Format: A table with all parameters specified in Section 4.
5.3. Latency
Objective: To determine the latency as defined in section 6.2 of
[RFC5695] and section 26.2 of [RFC2544] for each of the SR-MPLS
forwarding operations (PUSH, NEXT, CONTINUE). It is RECOMMENDED to
test all three test types discussed in Section 5.1.
Procedure: Similar to Section 5.1. It is OPTIONAL to improve the
procedure according to section 7.2 of [RFC8219] with calculations for
typical and worst-case latency.
Reporting Format: A table with all parameters specified in Section 4.
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5.4. Frame Loss
Objective: To determine the frame-loss rate (as defined in section
6.3 of [RFC5695] and section 26.3 of [RFC2544]) for each of the SR-
MPLS forwarding operations of a DUT throughout the entire range of
input data rates and frame sizes. The primary idea is to see what
would be the frame loss under the overload conditions. It may be
that overloaded forwarding engine would forward less traffic than in
the situation close to the overload. Throughput may drop below the
possible maximum. As per section 26.3 of [RFC2544], it is
RECOMMENDED to have the data for all tested frame sizes with 10% load
step above the wire-speed throughput measured in Section 5.1. It is
RECOMMENDED to test all three test types discussed in Section 5.1.
Procedure: Similar to Section 5.1.
Reporting Format: A table with all parameters specified in Section 4.
5.5. System Recovery
Objective: To characterize the speed at which a DUT recovers from an
overload condition for each of the SR-MPLS forwarding operations. It
is RECOMMENDED to test all three test types discussed in Section 5.1.
Procedure: Similar to section 6.4 of [RFC5695] or section 26.5 of
[RFC2544]. Send a stream of frames at a rate 110% of the recorded
throughput rate or the maximum rate for the media, whichever is
lower, for at least 60 seconds. At Timestamp A reduce the frame rate
to 50% of the above rate and record the time of the last frame lost
(Timestamp B). The system recovery time is determined by subtracting
Timestamp B from Timestamp A. The test SHOULD be repeated a number
of times and the average of the recorded values being reported.
Reporting Format: A table with all parameters specified in Section 4.
5.6. Reset
All type of reset tests are OPTIONAL.
Objective: To characterize the speed at which a DUT recovers from a
device or software reset for each of the SR-MPLS forwarding
operations. According to section 1.3 of [RFC6201] it is possible to
measure frame loss or time stamps (depending on the test tool
capability). According to section 4 of [RFC6201] reset could be: 1)
hardware, 2) software, or 3) power interruption. All resets may be
partial, i.e. only for a particular part of hardware (line card) or
software (module). Especial interest may be to test redundant power
supplies or routing engines to make sure that reset does not affect
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the traffic. Hardware reset may be soft (command for reset) or hard
(physical removal and insertion of the module). These types of reset
SHOULD be treated as different. It is OPTIONAL to test all three
test types discussed in Section 5.1, typically they would give the
same result.
Procedure: It is inherited from [RFC6201] (see it for more details).
It is simple in essence: create the traffic, initiate a reset,
measure the time for the traffic lost.
Reporting Format: A table with all parameters specified in Section 4.
6. Security Considerations
Benchmarking methodologies are limited to technology characterization
in a laboratory environment, with dedicated address space and
constraints. 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
production networks. The benchmarking network topology is 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.
There are no specific security considerations within the scope of
this document.
7. IANA Considerations
This document has no IANA actions.
8. Acknowledgements
The authors would like to thank Al Morton, Gabor Lencse, Boris
Khasanov for the precious comments and suggestions.
9. References
9.1. Normative References
[RFC1242] Bradner, S., "Benchmarking Terminology for Network
Interconnection Devices", RFC 1242, DOI 10.17487/RFC1242,
July 1991, <https://www.rfc-editor.org/info/rfc1242>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544,
DOI 10.17487/RFC2544, March 1999,
<https://www.rfc-editor.org/info/rfc2544>.
[RFC3330] IANA, "Special-Use IPv4 Addresses", RFC 3330,
DOI 10.17487/RFC3330, September 2002,
<https://www.rfc-editor.org/info/rfc3330>.
[RFC4773] Huston, G., "Administration of the IANA Special Purpose
IPv6 Address Block", RFC 4773, DOI 10.17487/RFC4773,
December 2006, <https://www.rfc-editor.org/info/rfc4773>.
[RFC4814] Newman, D. and T. Player, "Hash and Stuffing: Overlooked
Factors in Network Device Benchmarking", RFC 4814,
DOI 10.17487/RFC4814, March 2007,
<https://www.rfc-editor.org/info/rfc4814>.
[RFC5695] Akhter, A., Asati, R., and C. Pignataro, "MPLS Forwarding
Benchmarking Methodology for IP Flows", RFC 5695,
DOI 10.17487/RFC5695, November 2009,
<https://www.rfc-editor.org/info/rfc5695>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8219] Georgescu, M., Pislaru, L., and G. Lencse, "Benchmarking
Methodology for IPv6 Transition Technologies", RFC 8219,
DOI 10.17487/RFC8219, August 2017,
<https://www.rfc-editor.org/info/rfc8219>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing with the MPLS Data Plane", RFC 8660,
DOI 10.17487/RFC8660, December 2019,
<https://www.rfc-editor.org/info/rfc8660>.
9.2. Informative References
[ETSI-GR-NFV-TST-007]
ETSI, "ETSI GR NFV-TST 007: Network Functions
Virtualisation (NFV) Release 3; Testing; Guidelines on
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Interoperability Testing for MANO", 2020,
<https://www.etsi.org/deliver/etsi_gr/NFV-
TST/001_099/007/03.01.01_60/gr_NFV-TST007v030101p.pdf>.
[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., and
D. Jain, "Advertising Segment Routing Policies in BGP",
Work in Progress, Internet-Draft, draft-ietf-idr-segment-
routing-te-policy-25, 26 September 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
segment-routing-te-policy-25>.
[I-D.ietf-rtgwg-segment-routing-ti-lfa]
Litkowski, S., Bashandy, A., Filsfils, C., Francois, P.,
Decraene, B., and D. Voyer, "Topology Independent Fast
Reroute using Segment Routing", Work in Progress,
Internet-Draft, draft-ietf-rtgwg-segment-routing-ti-lfa-
11, 30 June 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-rtgwg-segment-routing-ti-lfa-11>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC6201] Asati, R., Pignataro, C., Calabria, F., and C. Olvera,
"Device Reset Characterization", RFC 6201,
DOI 10.17487/RFC6201, March 2011,
<https://www.rfc-editor.org/info/rfc6201>.
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
2015, <https://www.rfc-editor.org/info/rfc7432>.
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[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>.
[RFC8665] Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler,
H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", RFC 8665,
DOI 10.17487/RFC8665, December 2019,
<https://www.rfc-editor.org/info/rfc8665>.
[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
Extensions for Segment Routing", RFC 8667,
DOI 10.17487/RFC8667, December 2019,
<https://www.rfc-editor.org/info/rfc8667>.
[RFC8669] Previdi, S., Filsfils, C., Lindem, A., Ed., Sreekantiah,
A., and H. Gredler, "Segment Routing Prefix Segment
Identifier Extensions for BGP", RFC 8669,
DOI 10.17487/RFC8669, December 2019,
<https://www.rfc-editor.org/info/rfc8669>.
[RFC9004] Morton, A., "Updates for the Back-to-Back Frame Benchmark
in RFC 2544", RFC 9004, DOI 10.17487/RFC9004, May 2021,
<https://www.rfc-editor.org/info/rfc9004>.
[RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
A., and P. Mattes, "Segment Routing Policy Architecture",
RFC 9256, DOI 10.17487/RFC9256, July 2022,
<https://www.rfc-editor.org/info/rfc9256>.
Authors' Addresses
Giuseppe Fioccola
Huawei Technologies
Palazzo Verrocchio, Centro Direzionale Milano 2
20054 Segrate (Milan)
Italy
Email: giuseppe.fioccola@huawei.com
Eduard Vasilenko
Huawei Technologies
17/4 Krylatskaya str.
Moscow
Email: vasilenko.eduard@huawei.com
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Paolo Volpato
Huawei Technologies
Palazzo Verrocchio, Centro Direzionale Milano 2
20054 Segrate (Milan)
Italy
Email: paolo.volpato@huawei.com
Luis Miguel Contreras Murillo
Telefonica
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
Bruno Decraene
Orange
France
Email: bruno.decraene@orange.com
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