Network Working Group S. Poretsky
Internet Draft Allot Communications
Expires: April 2009
Intended Status: Informational Brent Imhoff
Juniper Networks
October 15, 2008
Benchmarking Methodology for
Link-State IGP Data Plane Route Convergence
<draft-ietf-bmwg-igp-dataplane-conv-meth-16.txt>
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ABSTRACT
This document describes the methodology for benchmarking Interior
Gateway Protocol (IGP) Route Convergence. The methodology is to
be used for benchmarking IGP convergence time through externally
observable (black box) data plane measurements. The methodology
can be applied to any link-state IGP, such as ISIS and OSPF.
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Table of Contents
1. Introduction ...............................................2
2. Existing definitions .......................................2
3. Test Setup..................................................3
3.1 Test Topologies............................................3
3.2 Test Considerations........................................5
3.3 Reporting Format...........................................8
4. Test Cases..................................................9
4.1 Convergence Due to Local Interface Failure.................9
4.2 Convergence Due to Remote Interface Failure................10
4.3 Convergence Due to Local Administrative Shutdown...........11
4.4 Convergence Due to Layer 2 Session Loss....................11
4.5 Convergence Due to Loss of IGP Adjacency...................12
4.6 Convergence Due to Route Withdrawal........................13
4.7 Convergence Due to Cost Change.............................14
4.8 Convergence Due to ECMP Member Interface Failure...........15
4.9 Convergence Due to ECMP Member Remote Interface Failure....16
4.10 Convergence Due to Parallel Link Interface Failure........16
5. IANA Considerations.........................................17
6. Security Considerations.....................................17
7. Acknowledgements............................................17
8. References..................................................18
9. Author's Address............................................18
1. Introduction
This document describes the methodology for benchmarking Interior
Gateway Protocol (IGP) Route Convergence. The applicability of this
testing is described in [Po07a] and the new terminology that it
introduces is defined in [Po07t]. Service Providers use IGP
Convergence time as a key metric of router design and architecture.
Customers of Service Providers observe convergence time by packet
loss, so IGP Route Convergence is considered a Direct Measure of
Quality (DMOQ). The test cases in this document are black-box tests
that emulate the network events that cause route convergence, as
described in [Po07a]. The black-box test designs benchmark the data
plane and account for all of the factors contributing to convergence
time, as discussed in [Po07a]. The methodology (and terminology) for
benchmarking route convergence can be applied to any link-state IGP
such as ISIS [Ca90] and OSPF [Mo98] and others. These methodologies
apply to IPv4 and IPv6 traffic and IGPs.
2. Existing definitions
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
[Br97]. 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.
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This document adopts the definition format in Section 2 of RFC 1242
[Br91]. This document uses much of the terminology defined in
[Po07t]. This document uses existing terminology defined in other
BMWG work. Examples include, but are not limited to:
Throughput [Ref.[Br91], section 3.17]
Device Under Test (DUT) [Ref.[Ma98], section 3.1.1]
System Under Test (SUT) [Ref.[Ma98], section 3.1.2]
Out-of-order Packet [Ref.[Po06], section 3.3.2]
Duplicate Packet [Ref.[Po06], section 3.3.3]
Packet Loss [Ref.[Po07t], Section 3.5]
3. Test Setup
3.1 Test Topologies
Figure 1 shows the test topology to measure IGP Route Convergence
due to local Convergence Events such as Link Failure, Layer 2
Session Failure, IGP Adjacency Failure, Route Withdrawal, and route
cost change. These test cases discussed in section 4 provide route
convergence times that include the Event Detection time, SPF
Processing time, and FIB Update time. These times are measured
by observing packet loss in the data plane at the Tester.
Figure 2 shows the test topology to measure IGP Route Convergence
time due to remote changes in the network topology. These times
are measured by observing packet loss in the data plane at the
Tester. In this topology the three routers are considered a System
Under Test (SUT). A Remote Interface [Po07t] failure on router R2
MUST result in convergence of traffic to router R3. NOTE: All
routers in the SUT must be the same model and identically
configured.
Figure 3 shows the test topology to measure IGP Route Convergence
time with members of an Equal Cost Multipath (ECMP) Set. These
times are measured by observing packet loss in the data plane at
the Tester. In this topology, the DUT is configured with each
Egress interface as a member of an ECMP set and the Tester emulates
multiple next-hop routers (emulates one router for each member).
--------- Ingress Interface ---------
| |<--------------------------------| |
| | | |
| | Preferred Egress Interface | |
| DUT |-------------------------------->| Tester|
| | | |
| |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>| |
| | Next-Best Egress Interface | |
--------- ---------
Figure 1. Test Topology 1: IGP Convergence Test Topology
for Local Changes
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----- ---------
| | Preferred | |
----- |R2 |---------------------->| |
| |-->| | Egress Interface | |
| | ----- | |
|R1 | |Tester |
| | ----- | |
| |-->| | Next-Best | |
----- |R3 |~~~~~~~~~~~~~~~~~~~~~~>| |
^ | | Egress Interface | |
| ----- ---------
| |
|--------------------------------------
Ingress Interface
Figure 2. Test Topology 2: IGP Convergence Test Topology
for Convergence Due to Remote Changes
--------- Ingress Interface ---------
| |<--------------------------------| |
| | | |
| | ECMP Set Interface 1 | |
| DUT |-------------------------------->| Tester|
| | . | |
| | . | |
| | . | |
| |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>| |
| | ECMP Set Interface N | |
--------- ---------
Figure 3. Test Topology 3: IGP Convergence Test Topology
for ECMP Convergence
--------- Ingress Interface ---------
| |<--------------------------------| |
| | | |
| | Parallel Link Interface 1 | |
| DUT |-------------------------------->| Tester|
| | . | |
| | . | |
| | . | |
| |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>| |
| | Parallel Link Interface N | |
--------- ---------
Figure 4. Test Topology 4: IGP Convergence Test Topology
for Parallel Link Convergence
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Figure 4 shows the test topology to measure IGP Route Convergence
time with members of a Parallel Link. These times are measured by
observing packet loss in the data plane at the Tester. In this
topology, the DUT is configured with each Egress interface as a
member of a Parallel Link and the Tester emulates the single
next-hop router.
3.2 Test Considerations
3.2.1 IGP Selection
The test cases described in section 4 MAY be used for link-state
IGPs, such as ISIS or OSPF. The Route Convergence test methodology
is identical. The IGP adjacencies are established on the Preferred
Egress Interface and Next-Best Egress Interface.
3.2.2 Routing Protocol Configuration
The obtained results for IGP Route Convergence may vary if
other routing protocols are enabled and routes learned via those
protocols are installed. IGP convergence times MUST be benchmarked
without routes installed from other protocols.
3.2.3 IGP Route Scaling
The number of IGP routes will impact the measured IGP Route
Convergence. To obtain results similar to those that would be
observed in an operational network, it is RECOMMENDED that the
number of installed routes and nodes closely approximates that
of the network (e.g. thousands of routes with tens of nodes).
The number of areas (for OSPF) and levels (for ISIS) can impact
the benchmark results.
3.2.4 Timers
There are some timers that will impact the measured IGP Convergence
time. Benchmarking metrics may be measured at any fixed values for
these timers. It is RECOMMENDED that the following timers be
configured to the minimum values listed:
Timer Recommended Value
----- -----------------
Link Failure Indication Delay <10milliseconds
IGP Hello Timer 1 second
IGP Dead-Interval 3 seconds
LSA Generation Delay 0
LSA Flood Packet Pacing 0
LSA Retransmission Packet Pacing 0
SPF Delay 0
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3.2.5 Interface Types
All test cases in this methodology document may be executed with any
interface type. All interfaces MUST be the same media and Throughput
[Br91][Br99] for each test case. The type of media may dictate which
test cases may be executed. This is because each interface type has
a unique mechanism for detecting link failures and the speed at which
that mechanism operates will influence the measure results. Media
and protocols MUST be configured for minimum failure detection delay
to minimize the contribution to the measured Convergence time. For
example, configure SONET with the minimum carrier-loss-delay. All
interfaces SHOULD be configured as point-to-point.
3.2.6 Packet Sampling Interval
The Packet Sampling Interval [Po07t] value is the fastest measurable
Rate-Derived Convergence Time [Po07t]. The RECOMMENDED value for the
Packet Sampling Interval is 10 milliseconds. Rate-Derived Convergence
Time is the preferred benchmark for IGP Route Convergence. This
benchmark must always be reported when the Packet Sampling Interval
is set <= 10 milliseconds on the test equipment. If the test
equipment does not permit the Packet Sampling Interval to be set as
low as 10 milliseconds, then both the Rate-Derived Convergence Time
and Loss-Derived Convergence Time [Po07t] MUST be reported.
3.2.7 Offered Load
The offered load MUST be the Throughput of the device as defined in
[Br91] and benchmarked in [Br99] at a fixed packet size. At least
one packet per route in the FIB for all routes in the FIB MUST be
offered to the DUT within the Packet Sampling interval. Packet size
is measured in bytes and includes the IP header and payload. The
packet size is selectable and MUST be recorded. The Forwarding
Rate [Ma98] MUST be measured at the Preferred Egress Interface and
the Next-Best Egress Interface. The duration of offered load MUST
be greater than the convergence time. The destination addresses
for the offered load MUST be distributed such that all routes are
matched and each route is offered an equal share of the total
Offered Load. This requirement for the Offered Load to be
distributed to match all destinations in the route table creates
separate flows that are offered to the DUT. The capability of the
Tester to measure packet loss for each individual flow (identified
by the destination address matching a route entry) and the scale
for the number of individual flows for which it can measure packet
loss should be considered when benchmarking Route-Specific
Convergence [Po07t].
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3.2.8 Selection of Convergence Time Benchmark Metrics
The methodologies in the section 4 test cases MAY be applied to
benchmark Full Convergence and Route-Specific Convergence with
benchmarking metrics First Route Convergence Time, Loss-Derived
Convergence Time, Rate-Derived Convergence Time, Reversion
Convergence Time, and Route-Specific Convergence Times [Po07t].
When benchmarking Full Convergence the Rate-Derived Convergence
Time benchmarking metric MAY be measured. When benchmarking
Route-Specific Convergence the Route-Specific Convergence Time
benchmarking metric MUST be measured and Full Convergence MAY be
obtained from max(Route-Specific Convergence Time). The First
Route Convergence Time benchmarking metric MAY be measured when
benchmarking either Full Convergence or Route-Specific Convergence.
3.2.9 Tester Capabilities
It is RECOMMENDED that the Tester used to execute each test case
have the following capabilities:
1. Ability to insert a timestamp in each data packet's IP
payload.
2. An internal time clock to control timestamping, time
measurements, and time calculations.
3. Ability to distinguish traffic load received on the Preferred
and Next-Best interfaces.
4. Ability to disable or tune specific Layer-2 and Layer-3
protocol functions on any interface(s).
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3.3 Reporting Format
For each test case, it is recommended that the reporting table below
is completed and all time values SHOULD be reported with resolution
as specified in [Po07t].
Parameter Units
--------- -----
Test Case test case number
Test Topology (1, 2, 3, or 4)
IGP (ISIS, OSPF, other)
Interface Type (GigE, POS, ATM, other)
Packet Size offered to DUT bytes
IGP Routes advertised to DUT number of IGP routes
Nodes in emulated network number of nodes
Packet Sampling Interval on Tester milliseconds
IGP Timer Values configured on DUT:
Interface Failure Indication Delay seconds
IGP Hello Timer seconds
IGP Dead-Interval seconds
LSA Generation Delay seconds
LSA Flood Packet Pacing seconds
LSA Retransmission Packet Pacing seconds
SPF Delay seconds
Forwarding Metrics
Total Packets Offered to DUT number of Packets
Total Packets Routed by DUT number of Packets
Convergence Packet Loss number of Packets
Out-of-Order Packets number of Packets
Duplicate Packets number of Packets
Convergence Benchmarks
Full Convergence
First Route Convergence Time seconds
Rate-Derived Convergence Time seconds
Loss-Derived Convergence Time seconds
Route-Specific Convergence
Number of Routes Measured number of flows
Route-Specific Convergence Time[n] array of seconds
Minimum R-S Convergence Time seconds
Maximum R-S Convergence Time seconds
Median R-S Convergence Time seconds
Average R-S Convergence Time seconds
Reversion
Reversion Convergence Time seconds
First Route Convergence Time seconds
Route-Specific Convergence
Number of Routes Measured number of flows
Route-Specific Convergence Time[n] array of seconds
Minimum R-S Convergence Time seconds
Maximum R-S Convergence Time seconds
Median R-S Convergence Time seconds
Average R-S Convergence Time seconds
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4. Test Cases
It is RECOMMENDED that all applicable test cases be executed for
best characterization of the DUT. The test cases follow a generic
procedure tailored to the specific DUT configuration and Convergence
Event[Po07t]. This generic procedure is as follows:
1. Establish DUT configuration and install routes.
2. Send offered load with traffic traversing Preferred Egress
Interface [Po07t].
3. Introduce Convergence Event to force traffic to Next-Best
Egress Interface [Po07t].
4. Measure First Route Convergence Time.
5. Measure Full Convergence from Loss-Derived Convergence Time,
Rate-Derived Convergence Time, and optionally the
Route-Specific Convergence Times.
6. Wait the Sustained Convergence Validation Time to ensure there
no residual packet loss.
7. Recover from Convergence Event.
8. Measure Reversion Convergence Time, and optionally the First
Route Convergence Time and Route-Specific Convergence Times.
4.1 Convergence Due to Local Interface Failure
Objective
To obtain the IGP Route Convergence due to a local link failure event
at the DUT's Local Interface.
Procedure
1. Advertise matching IGP routes from Tester to DUT on Preferred
Egress Interface [Po07t] and Next-Best Egress Interface [Po07t]
using the topology shown in Figure 1. Set the cost of the routes
so that the Preferred Egress Interface is the preferred next-hop.
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
3. Verify traffic is routed over Preferred Egress Interface.
4. Remove link on DUT's Preferred Egress Interface. This is the
Convergence Event [Po07t] that produces the Convergence Event
Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as DUT detects the
link down event and begins to converge IGP routes and traffic
over the Next-Best Egress Interface.
6. Measure Rate-Derived Convergence Time [Po07t] as DUT detects the
link down event and converges all IGP routes and traffic over
the Next-Best Egress Interface. Optionally, Route-Specific
Convergence Times [Po07t] MAY be measured.
7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Restore link on DUT's Preferred Egress Interface.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT detects the link up event and
converges all IGP routes and traffic back to the Preferred
Egress Interface.
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Results
The measured IGP Convergence time is influenced by the Local
link failure indication, SPF delay, SPF Hold time, SPF Execution
Time, Tree Build Time, and Hardware Update Time [Po07a].
4.2 Convergence Due to Remote Interface Failure
Objective
To obtain the IGP Route Convergence due to a Remote Interface
Failure event.
Procedure
1. Advertise matching IGP routes from Tester to SUT on
Preferred Egress Interface [Po07t] and Next-Best Egress
Interface [Po07t] using the topology shown in Figure 2.
Set the cost of the routes so that the Preferred Egress
Interface is the preferred next-hop.
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
SUT on Ingress Interface [Po07t].
3. Verify traffic is routed over Preferred Egress Interface.
4. Remove link on Tester's Neighbor Interface [Po07t] connected to
SUT's Preferred Egress Interface. This is the Convergence Event
[Po07t] that produces the Convergence Event Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as SUT detects the
link down event and begins to converge IGP routes and traffic
over the Next-Best Egress Interface.
6. Measure Rate-Derived Convergence Time [Po07t] as SUT detects
the link down event and converges all IGP routes and traffic
over the Next-Best Egress Interface. Optionally, Route-Specific
Convergence Times [Po07t] MAY be measured.
7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Restore link on Tester's Neighbor Interface connected to
DUT's Preferred Egress Interface.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT detects the link up event and
converges all IGP routes and traffic back to the Preferred Egress
Interface.
Results
The measured IGP Convergence time is influenced by the link failure
indication, LSA/LSP Flood Packet Pacing, LSA/LSP Retransmission
Packet Pacing, LSA/LSP Generation time, SPF delay, SPF Hold time,
SPF Execution Time, Tree Build Time, and Hardware Update Time
[Po07a]. This test case may produce Stale Forwarding [Po07t] due to
microloops which may increase the measured convergence times.
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4.3 Convergence Due to Local Adminstrative Shutdown
Objective
To obtain the IGP Route Convergence due to a administrative shutdown
at the DUT's Local Interface.
Procedure
1. Advertise matching IGP routes from Tester to DUT on
Preferred Egress Interface [Po07t] and Next-Best Egress Interface
[Po07t] using the topology shown in Figure 1. Set the cost of
the routes so that the Preferred Egress Interface is the
preferred next-hop.
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
3. Verify traffic is routed over Preferred Egress Interface.
4. Perform adminstrative shutdown on the DUT's Preferred Egress
Interface. This is the Convergence Event [Po07t] that produces
the Convergence Event Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as DUT detects the
link down event and begins to converge IGP routes and traffic
over the Next-Best Egress Interface.
6. Measure Rate-Derived Convergence Time [Po07t] as DUT converges
all IGP routes and traffic over the Next-Best Egress Interface.
Optionally, Route-Specific Convergence Times [Po07t] MAY be
measured.
7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Restore Preferred Egress Interface by administratively enabling
the interface.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT detects the link up event and
converges all IGP routes and traffic back to the Preferred
Egress Interface.
Results
The measured IGP Convergence time is influenced by SPF delay,
SPF Hold time, SPF Execution Time, Tree Build Time, and Hardware
Update Time [Po07a].
4.4 Convergence Due to Layer 2 Session Loss
Objective
To obtain the IGP Route Convergence due to a local Layer 2 loss.
Procedure
1. Advertise matching IGP routes from Tester to DUT on
Preferred Egress Interface [Po07t] and Next-Best Egress Interface
[Po07t] using the topology shown in Figure 1. Set the cost of
the routes so that the IGP routes along the Preferred Egress
Interface is the preferred next-hop.
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
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3. Verify traffic is routed over Preferred Egress Interface.
4. Tester removes Layer 2 session from DUT's Preferred Egress
Interface [Po07t]. It is RECOMMENDED that this be achieved with
messaging, but the method MAY vary with the Layer 2 protocol.
This is the Convergence Event [Po07t] that produces the
Convergence Event Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as DUT detects the
Layer 2 session down event and begins to converge IGP routes and
traffic over the Next-Best Egress Interface.
6. Measure Rate-Derived Convergence Time [Po07t] as DUT detects the
Layer 2 session down event and converges all IGP routes and
traffic over the Next-Best Egress Interface. Optionally,
Route-Specific Convergence Times [Po07t] MAY be measured.
7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Restore Layer 2 session on DUT's Preferred Egress Interface.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT detects the session up event
and converges all IGP routes and traffic over the Preferred Egress
Interface.
Results
The measured IGP Convergence time is influenced by the Layer 2
failure indication, SPF delay, SPF Hold time, SPF Execution
Time, Tree Build Time, and Hardware Update Time [Po07a].
4.5 Convergence Due to Loss of IGP Adjacency
Objective
To obtain the IGP Route Convergence due to loss of the IGP
Adjacency.
Procedure
1. Advertise matching IGP routes from Tester to DUT on
Preferred Egress Interface [Po07t] and Next-Best Egress Interface
[Po07t] using the topology shown in Figure 1. Set the cost of
the routes so that the Preferred Egress Interface is the
preferred next-hop.
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
3. Verify traffic is routed over Preferred Egress Interface.
4. Remove IGP adjacency from Tester's Neighbor Interface [Po07t]
connected to Preferred Egress Interface. The Layer 2 session
MUST be maintained. This is the Convergence Event [Po07t] that
produces the Convergence Event Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as DUT detects the
loss of IGP adjacency and begins to converge IGP routes and
traffic over the Next-Best Egress Interface.
6. Measure Rate-Derived Convergence Time [Po07t] as DUT detects the
IGP session failure event and converges all IGP routes and
traffic over the Next-Best Egress Interface. Optionally,
Route-Specific Convergence Times [Po07t] MAY be measured.
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7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Restore IGP session on DUT's Preferred Egress Interface.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT detects the session recovery
event and converges all IGP routes and traffic over the
Preferred Egress Interface.
Results
The measured IGP Convergence time is influenced by the IGP Hello
Interval, IGP Dead Interval, SPF delay, SPF Hold time, SPF
Execution Time, Tree Build Time, and Hardware Update Time [Po07a].
4.6 Convergence Due to Route Withdrawal
Objective
To obtain the IGP Route Convergence due to Route Withdrawal.
Procedure
1. Advertise matching IGP routes from Tester to DUT on Preferred
Egress Interface [Po07t] and Next-Best Egress Interface [Po07t]
using the topology shown in Figure 1. Set the cost of the routes
so that the Preferred Egress Interface is the preferred next-hop.
It is RECOMMENDED that the IGP routes be IGP external routes
for which the Tester would be emulating a preferred and a
next-best Autonomous System Border Router (ASBR).
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
3. Verify traffic is routed over Preferred Egress Interface.
4. Tester withdraws all IGP routes from DUT's Local Interface
on Preferred Egress Interface. The Tester records the time it
sends the withdrawal message(s). This MAY be achieved with
inclusion of a timestamp in the traffic payload. This is the
Convergence Event [Po07t] that produces the Convergence Event
Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as DUT detects the
route withdrawal event and begins to converge IGP routes and
traffic over the Next-Best Egress Interface. This is measured
from the time that the Tester sent the withdrawal message(s).
6. Measure Rate-Derived Convergence Time [Po07t] as DUT withdraws
routes and converges all IGP routes and traffic over the
Next-Best Egress Interface. Optionally, Route-Specific
Convergence Times [Po07t] MAY be measured.
7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Re-advertise IGP routes to DUT's Preferred Egress Interface.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT converges all IGP routes and
traffic over the Preferred Egress Interface.
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Results
The measured IGP Convergence time is the SPF Processing and FIB
Update time as influenced by the SPF or route calculation delay,
Hold time, Execution Time, and Hardware Update Time [Po07a].
4.7 Convergence Due to Cost Change
Objective
To obtain the IGP Route Convergence due to route cost change.
Procedure
1. Advertise matching IGP routes from Tester to DUT on Preferred
Egress Interface [Po07t] and Next-Best Egress Interface [Po07t]
using the topology shown in Figure 1. Set the cost of the routes
so that the Preferred Egress Interface is the preferred next-hop.
2. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
3. Verify traffic is routed over Preferred Egress Interface.
4. Tester increases cost for all IGP routes at DUT's Preferred
Egress Interface so that the Next-Best Egress Interface
has lower cost and becomes preferred path. This is the
Convergence Event [Po07t] that produces the Convergence Event
Instant [Po07t].
5. Measure First Route Convergence Time [Po07t] as DUT detects the
cost change event and begins to converge IGP routes and traffic
over the Next-Best Egress Interface.
6. Measure Rate-Derived Convergence Time [Po07t] as DUT detects the
cost change event and converges all IGP routes and traffic
over the Next-Best Egress Interface. Optionally, Route-Specific
Convergence Times [Po07t] MAY be measured.
7. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
8. Re-advertise IGP routes to DUT's Preferred Egress Interface
with original lower cost metric.
9. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT converges all IGP routes and
traffic over the Preferred Egress Interface.
Results
There should be no measured packet loss for this case.
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4.8 Convergence Due to ECMP Member Interface Failure
Objective
To obtain the IGP Route Convergence due to a local link failure event
of an ECMP Member.
Procedure
1. Configure ECMP Set as shown in Figure 3.
2. Advertise matching IGP routes from Tester to DUT on each ECMP
member.
3. Send offered load at measured Throughput with fixed packet size to
destinations matching all IGP routes from Tester to DUT on Ingress
Interface [Po07t].
4. Verify traffic is routed over all members of ECMP Set.
5. Remove link on Tester's Neighbor Interface [Po07t] connected to
one of the DUT's ECMP member interfaces. This is the Convergence
Event [Po07t] that produces the Convergence Event Instant [Po07t].
6. Measure First Route Convergence Time [Po07t] as DUT detects the
link down event and begins to converge IGP routes and traffic
over the other ECMP members.
7. Measure Rate-Derived Convergence Time [Po07t] as DUT detects
the link down event and converges all IGP routes and traffic
over the other ECMP members. At the same time measure
Out-of-Order Packets [Po06] and Duplicate Packets [Po06].
Optionally, Route-Specific Convergence Times [Po07t] MAY be
measured.
8. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
9. Restore link on Tester's Neighbor Interface connected to
DUT's ECMP member interface.
10. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and Route-Specific
Convergence Times [Po07t], as DUT detects the link up event and
converges IGP routes and some distribution of traffic over the
restored ECMP member.
Results
The measured IGP Convergence time is influenced by Local link
failure indication, Tree Build Time, and Hardware Update Time
[Po07a].
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4.9 Convergence Due to ECMP Member Remote Interface Failure
Objective
To obtain the IGP Route Convergence due to a remote interface
failure event for an ECMP Member.
Procedure
1. Configure ECMP Set as shown in Figure 2 in which the links
from R1 to R2 and R1 to R3 are members of an ECMP Set.
2. Advertise matching IGP routes from Tester to SUT to balance
traffic to each ECMP member.
3. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
SUT on Ingress Interface [Po07t].
4. Verify traffic is routed over all members of ECMP Set.
5. Remove link on Tester's Neighbor Interface to R2 or R3.
This is the Convergence Event [Po07t] that produces the
Convergence Event Instant [Po07t].
6. Measure First Route Convergence Time [Po07t] as SUT detects
the link down event and begins to converge IGP routes and
traffic over the other ECMP members.
7. Measure Rate-Derived Convergence Time [Po07t] as SUT detects
the link down event and converges all IGP routes and traffic
over the other ECMP members. At the same time measure
Out-of-Order Packets [Po06] and Duplicate Packets [Po06].
Optionally, Route-Specific Convergence Times [Po07t] MAY be
measured.
8. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
9. Restore link on Tester's Neighbor Interface to R2 or R3.
10. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and
Route-Specific Convergence Times [Po07t], as SUT detects
the link up event and converges IGP routes and some
distribution of traffic over the restored ECMP member.
Results
The measured IGP Convergence time is influenced by Local link
failure indication, Tree Build Time, and Hardware Update Time
[Po07a].
4.10 Convergence Due to Parallel Link Interface Failure
Objective
To obtain the IGP Route Convergence due to a local link failure
event for a Member of a Parallel Link. The links can be used
for data Load Balancing
Procedure
1. Configure Parallel Link as shown in Figure 4.
2. Advertise matching IGP routes from Tester to DUT on
each Parallel Link member.
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Link-State IGP Data Plane Route Convergence
3. Send offered load at measured Throughput with fixed packet
size to destinations matching all IGP routes from Tester to
DUT on Ingress Interface [Po07t].
4. Verify traffic is routed over all members of Parallel Link.
5. Remove link on Tester's Neighbor Interface [Po07t] connected to
one of the DUT's Parallel Link member interfaces. This is the
Convergence Event [Po07t] that produces the Convergence Event
Instant [Po07t].
6. Measure First Route Convergence Time [Po07t] as DUT detects the
link down event and begins to converge IGP routes and traffic
over the other Parallel Link members.
7. Measure Rate-Derived Convergence Time [Po07t] as DUT detects the
link down event and converges all IGP routes and traffic over
the other Parallel Link members. At the same time measure
Out-of-Order Packets [Po06] and Duplicate Packets [Po06].
Optionally, Route-Specific Convergence Times [Po07t] MAY be
measured.
8. Stop offered load. Wait 30 seconds for queues to drain.
Restart offered load.
9. Restore link on Tester's Neighbor Interface connected to
DUT's Parallel Link member interface.
10. Measure Reversion Convergence Time [Po07t], and optionally
measure First Route Convergence Time [Po07t] and
Route-Specific Convergence Times [Po07t], as DUT
detects the link up event and converges IGP routes and some
distribution of traffic over the restored Parallel Link member.
Results
The measured IGP Convergence time is influenced by the Local
link failure indication, Tree Build Time, and Hardware Update
Time [Po07a].
5. IANA Considerations
This document requires no IANA considerations.
6. Security Considerations
Documents of this type do not directly affect the security of
the Internet or corporate networks as long as benchmarking
is not performed on devices or systems connected to operating
networks.
7. Acknowledgements
Thanks to Sue Hares, Al Morton, Kevin Dubray, Ron Bonica, David Ward,
Kris Michielsen and the BMWG for their contributions to this work.
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8. References
8.1 Normative References
[Br91] Bradner, S., "Benchmarking Terminology for Network
Interconnection Devices", RFC 1242, IETF, March 1991.
[Br97] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997
[Br99] Bradner, S. and McQuaid, J., "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544, IETF, March 1999.
[Ca90] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual
Environments", RFC 1195, IETF, December 1990.
[Ma98] Mandeville, R., "Benchmarking Terminology for LAN
Switching Devices", RFC 2285, February 1998.
[Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.
[Po06] Poretsky, S., et al., "Terminology for Benchmarking
Network-layer Traffic Control Mechanisms", RFC 4689,
November 2006.
[Po07a] Poretsky, S., "Considerations for Benchmarking Link-State
IGP Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-16,
work in progress, October 2008.
[Po07t] Poretsky, S., Imhoff, B., "Benchmarking Terminology for
Link-State IGP Convergence",
draft-ietf-bmwg-igp-dataplane-conv-term-16, work in
progress, October 2008.
8.2 Informative References
None
9. Author's Address
Scott Poretsky
Allot Communications
67 South Bedford Street, Suite 400
Burlington, MA 01803
USA
Phone: + 1 508 309 2179
Email: sporetsky@allot.com
Brent Imhoff
Juniper Networks
1194 North Mathilda Ave
Sunnyvale, CA 94089
USA
Phone: + 1 314 378 2571
EMail: bimhoff@planetspork.com
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Poretsky and Imhoff [Page 19]
