draft-ietf-bmwg-igp-dataplane-conv-term-12.txt   draft-ietf-bmwg-igp-dataplane-conv-term-13.txt 
Network Working Group Network Working Group
INTERNET-DRAFT INTERNET-DRAFT
Expires in: August 2007 Expires in: January 2008
Intended Status: Informational Intended Status: Informational
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
Brent Imhoff Brent Imhoff
Juniper Networks Juniper Networks
February 2007
Terminology for Benchmarking Terminology for Benchmarking
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
<draft-ietf-bmwg-igp-dataplane-conv-term-12.txt> <draft-ietf-bmwg-igp-dataplane-conv-term-13.txt>
Intellectual Property Rights (IPR) statement: Intellectual Property Rights (IPR) statement:
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Status of this Memo Status of this Memo
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
skipping to change at page 2, line 10 skipping to change at page 2, line 10
Gateway Protocol (IGP) Route Convergence. The terminology is to Gateway Protocol (IGP) Route Convergence. The terminology is to
be used for benchmarking IGP convergence time through externally be used for benchmarking IGP convergence time through externally
observable (black box) data plane measurements. The terminology observable (black box) data plane measurements. The terminology
can be applied to any link-state IGP, such as ISIS and OSPF. can be applied to any link-state IGP, such as ISIS and OSPF.
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
Table of Contents Table of Contents
1. Introduction .................................................2 1. Introduction .................................................2
2. Existing definitions .........................................3 2. Existing definitions .........................................3
3. Term definitions..............................................3 3. Term definitions..............................................4
3.1 Convergence Event.........................................3 3.1 Convergence Event.........................................4
3.2 Route Convergence.........................................4 3.2 Route Convergence.........................................4
3.3 Network Convergence.......................................4 3.3 Network Convergence.......................................5
3.4 Full Convergence..........................................5 3.4 Full Convergence..........................................5
3.5 Convergence Packet Loss...................................5 3.5 Packet Loss...............................................6
3.6 Convergence Event Instant.................................6 3.6 Convergence Packet Loss...................................6
3.7 Convergence Recovery Instant..............................6 3.7 Convergence Event Instant.................................7
3.8 Rate-Derived Convergence Time.............................7 3.8 Convergence Recovery Instant..............................7
3.9 Convergence Event Transition..............................7 3.9 Rate-Derived Convergence Time.............................8
3.10 Convergence Recovery Transition..........................8 3.10 Convergence Event Transition.............................8
3.11 Loss-Derived Convergence Time............................8 3.11 Convergence Recovery Transition..........................9
3.12 Sustained Forwarding Convergence Time....................9 3.12 Loss-Derived Convergence Time............................9
3.13 Restoration Convergence Time.............................9 3.13 Sustained Forwarding Convergence Time....................10
3.14 Packet Sampling Interval.................................10 3.14 Restoration Convergence Time.............................11
3.15 Local Interface..........................................11 3.15 Packet Sampling Interval.................................12
3.16 Neighbor Interface.......................................11 3.16 Local Interface..........................................12
3.17 Remote Interface.........................................11 3.17 Neighbor Interface.......................................13
3.18 Preferred Egress Interface...............................12 3.18 Remote Interface.........................................13
3.19 Next-Best Egress Interface...............................12 3.19 Preferred Egress Interface...............................13
3.20 Stale Forwarding.........................................13 3.20 Next-Best Egress Interface...............................14
3.21 Nested Convergence Events................................13 3.21 Stale Forwarding.........................................14
4. IANA Considerations...........................................13 3.22 Nested Convergence Events................................15
5. Security Considerations.......................................14 4. IANA Considerations...........................................15
6. Acknowledgements..............................................14 5. Security Considerations.......................................15
7. Normative References..........................................14 6. Acknowledgements..............................................15
8. Author's Address..............................................15 7. References....................................................15
8. Author's Address..............................................16
1. Introduction 1. Introduction
This draft describes the terminology for benchmarking Interior This draft describes the terminology for benchmarking Interior
Gateway Protocol (IGP) Route Convergence. The motivation and Gateway Protocol (IGP) Route Convergence. The motivation and
applicability for this benchmarking is provided in [Po07a]. The applicability for this benchmarking is provided in [Po07a]. The
methodology to be used for this benchmarking is described in [Po07m]. methodology to be used for this benchmarking is described in [Po07m].
The methodology and terminology to be used for benchmarking Route The methodology and terminology to be used for benchmarking Route
Convergence can be applied to any link-state IGP such as ISIS [Ca90] Convergence can be applied to any link-state IGP such as ISIS [Ca90]
and OSPF [Mo98]. The data plane is measured to obtain black-box and OSPF [Mo98]. The data plane is measured to obtain black-box
(externally observable) convergence benchmarking metrics. The (externally observable) convergence benchmarking metrics. The
purpose of this document is to introduce new terms required to purpose of this document is to introduce new terms required to
complete execution of the IGP Route Convergence Methodology [Po07m]. complete execution of the IGP Route Convergence Methodology [Po07m].
These terms apply to IPv4 and IPv6 traffic and IGPs. These terms apply to IPv4 and IPv6 traffic and IGPs.
IGP Data Plane Route Convergence
An example of Route Convergence as observed and measured from the An example of Route Convergence as observed and measured from the
data plane is shown in Figure 1. The graph in Figure 1 shows data plane is shown in Figure 1. The graph in Figure 1 shows
Forwarding Rate versus Time. Time 0 on the X-axis is on the far Forwarding Rate versus Time. Time 0 on the X-axis is on the far
right of the graph. The Offered Load to the ingress interface of right of the graph. The Offered Load to the ingress interface of
the DUT SHOULD equal the measured maximum Throughput [Ba99][Ma98] the DUT SHOULD equal the measured maximum Throughput [Ba99][Ma98]
of the DUT and the Forwarding Rate [Ma98] is measured at the egress of the DUT and the Forwarding Rate [Ma98] is measured at the egress
interfaces of the DUT. The components of the graph and the metrics interfaces of the DUT. The components of the graph and the metrics
are defined in the Term Definitions section. are defined in the Term Definitions section.
IGP Data Plane Route Convergence
Convergence Convergence Convergence Convergence
Recovery Event Recovery Event
Instant Instant Time = 0sec Instant Instant Time = 0sec
Forwarding Rate = ^ ^ ^ Offered Load = Forwarding Rate = ^ ^ ^ Offered Load =
Offered Load --> ------\ Packet /-------- <---Max Throughput Offered Load --> ------\ Packet /-------- <---Max Throughput
\ Loss /<----Convergence \ Loss /<----Convergence
Convergence------->\ / Event Transition Convergence------->\ / Event Transition
Recovery Transition \ / Recovery Transition \ /
\_____/<------Maximum Packet Loss \_____/<------Maximum Packet Loss
X-axis = Time X-axis = Time
Y-axis = Forwarding Rate Y-axis = Forwarding Rate
Figure 1. Convergence Graph Figure 1. Convergence Graph
2. Existing definitions 2. Existing definitions
This document uses existing terminology defined in other BMWG
work. Examples include, but are not limited to:
Latency [Ref.[Ba91], section 3.8]
Frame Loss Rate [Ref.[Ba91], section 3.6]
Throughput [Ref.[Ba91], 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 Reordering [Ref.[Mo06], section 3.3]
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119 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 [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 intent of standards track documents as clear as possible. While this
document uses these keywords, this document is not a standards track document uses these keywords, this document is not a standards track
document. The term Throughput is defined in [Ba91] and [Ba99]. document.
IGP Data Plane Route Convergence
3. Term Definitions 3. Term Definitions
3.1 Convergence Event 3.1 Convergence Event
Definition: Definition:
The occurrence of a planned or unplanned action in the network The occurrence of a planned or unplanned action in the network
that results in a change in the egress interface of the Device that results in a change in the egress interface of the Device
Under Test (DUT) for Under Test (DUT) for routed packets.
routed packets.
Discussion: Discussion:
Convergence Events include link loss, routing protocol session Convergence Events include link loss, routing protocol session
loss, router failure, configuration change, and better next-hop loss, router failure, configuration change, and better next-hop
learned via a routing protocol. learned via a routing protocol.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Convergence Packet Loss Convergence Packet Loss
Convergence Event Instant Convergence Event Instant
IGP Data Plane Route Convergence
3.2 Route Convergence 3.2 Route Convergence
Definition: Definition:
Recovery from a Convergence Event indicated by the DUT Route Convergence is the action to update all components of the
Throughput equal to the offered load. router with the most recent route change(s) including the
Routing Information Base (RIB) and Forwarding Information Base
(FIB), along with software and hardware tables, such that
forwarding is successful for one or more destinations.
Discussion: Discussion:
Route Convergence is the action of all components of the router Route Convergence is required after a Convergence Event.
being updated with the most recent route change(s) including the Route Convergence can be observed externally by the rerouting
Routing Information Base (RIB) and Forwarding Information Base of data traffic to the next-best egress interface. Also,
(FIB), along with software and hardware tables. Route Route Convergence may or may not be sustained over time.
Convergence can be observed externally by the rerouting of data
Traffic to a new egress interface.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Network Convergence Network Convergence
Full Convergence Full Convergence
Convergence Event Convergence Event
IGP Data Plane Route Convergence
3.3 Network Convergence 3.3 Network Convergence
Definition: Definition:
The completion of updating of all routing tables, including the The completion of updating of all routing tables, including the
FIB, in all routers throughout the network. FIB, in all routers throughout the network.
Discussion: Discussion:
Network Convergence is bounded by the sum of Route Convergence Network Convergence requires completion of all Route Convergence
for all routers in the network. Network Convergence can be operations for all routers in the network following a
determined by recovery of the Throughput to equal the offered Convergence Event. Network Convergence can be observed by
load, with no Stale Forwarding, and no blenders [Ca01][Ci03]. recovery of System Under Test (SUT) Throughput to equal the
offered load, with no Stale Forwarding, and no Blenders
[Ca01][Ci03].
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Route Convergence Route Convergence
Stale Forwarding Stale Forwarding
IGP Data Plane Route Convergence
3.4 Full Convergence 3.4 Full Convergence
Definition: Definition:
Route Convergence for an entire FIB. Route Convergence for an entire FIB in which complete recovery
from the Convergence Event is indicated by the DUT Throughput
equal to the offered load.
Discussion: Discussion:
When benchmarking convergence, it is useful to measure When benchmarking convergence, it is useful to measure
the time to converge an entire FIB. For example, the time to converge an entire FIB. For example,
a Convergence Event can be produced for an OSPF table of a Convergence Event can be produced for an OSPF table of
5000 routes so that the time to converge routes 1 through 5000 routes so that the time to converge routes 1 through
5000 is measured. Full Convergence is externally observable 5000 is measured. Full Convergence is externally observable
from the data plane when the Throughput of the data from the data plane when the Throughput of the data
plane traffic on the Next-Best Egress Interface equals the plane traffic on the Next-Best Egress Interface equals the
offered load. offered load.
Measurement Units: Measurement Units:
N/A N/A
Issues: None Issues: None
See Also: See Also:
Network Convergence Network Convergence
Route Convergence Route Convergence
Convergence Event Convergence Event
IGP Data Plane Route Convergence
3.5 Convergence Packet Loss 3.5 Packet Loss
Definition: Definition:
The amount of packet loss produced by a Convergence Event The number of packets that should have been forwarded
until Route Convergence occurs. by a DUT under steady state (constant) load that were
not forwarded due to lack of resources.
Discussion: Discussion:
Packet loss can be observed as a reduction of forwarded traffic Packet Loss is a modified version of the term "Frame Loss Rate"
from the maximum Throughput. Convergence Packet Loss as defined in [Ba91]. The term "Frame Loss" is intended for
includes packets that were lost and packets that were delayed Ethernet Frames while "Packet Loss" is intended for IP packets.
due to buffering. The maximum Convergence Packet Loss observed Packet Loss can be measured as a reduction in forwarded traffic
in a Packet Sampling Interval may or may not reach 100% during from the Throughput [Ba91] of the DUT.
Route Convergence (see Figure 1).
Measurement units:
Number of N-octet offered packets that are not forwarded.
Issues: None
See Also:
Convergence Packet Loss
3.6 Convergence Packet Loss
Definition:
The number of packets lost due to a Convergence Event
until Full Convergence occurs.
Discussion:
Convergence Packet Loss includes packets that were lost and
packets that were delayed due to buffering. The Convergence
Packet Loss observed in a Packet Sampling Interval may or may
not be equal to the number of packets in the offered load
during the interval following a Convergence Event (see Figure
1).
Measurement Units: Measurement Units:
number of packets number of packets
Issues: None Issues: None
See Also: See Also:
Packet Loss
Route Convergence Route Convergence
Convergence Event Convergence Event
Rate-Derived Convergence Time
Loss-Derived Convergence Time
Packet Sampling Interval Packet Sampling Interval
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
3.6 Convergence Event Instant 3.7 Convergence Event Instant
Definition: Definition:
The time instant that a Convergence Event becomes observable in The time instant that a Convergence Event becomes observable in
the data plane. the data plane.
Discussion: Discussion:
Convergence Event Instant is observable from the data Convergence Event Instant is observable from the data
plane as the precise time that the device under test begins plane as the precise time that the device under test begins
to exhibit packet loss. to exhibit packet loss.
skipping to change at page 6, line 28 skipping to change at page 7, line 28
hh:mm:ss:nnn, where 'nnn' is milliseconds hh:mm:ss:nnn, where 'nnn' is milliseconds
Issues: Issues:
None None
See Also: See Also:
Convergence Event Convergence Event
Convergence Packet Loss Convergence Packet Loss
Convergence Recovery Instant Convergence Recovery Instant
3.7 Convergence Recovery Instant 3.8 Convergence Recovery Instant
Definition: Definition:
The time instant that Full Convergence is measured The time instant that Full Convergence is measured
and then maintained for an interval of duration equal to and then maintained for an interval of duration equal to
the Sustained Forwarding Convergence Time the Sustained Forwarding Convergence Time
Discussion: Discussion:
Convergence Recovery Instant is measurable from the data Convergence Recovery Instant is measurable from the data
plane as the precise time that the device under test plane as the precise time that the device under test
achieves Full Convergence. achieves Full Convergence.
Measurement Units: Measurement Units:
hh:mm:ss:uuu hh:mm:ss:nnn, where 'nnn' is milliseconds
Issues: Issues:
None None
See Also: See Also:
Sustained Forwarding Convergence Time Sustained Forwarding Convergence Time
Convergence Packet Loss Convergence Packet Loss
Convergence Event Instant Convergence Event Instant
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
3.8 Rate-Derived Convergence Time 3.9 Rate-Derived Convergence Time
Definition: Definition:
The amount of time for Convergence Packet Loss to persist upon The amount of time for Convergence Packet Loss to persist upon
occurrence of a Convergence Event until occurrence of Route occurrence of a Convergence Event until occurrence of Route
Convergence. Convergence.
Rate-Derived Convergence Time can be measured as the time Rate-Derived Convergence Time can be measured as the time
difference from the Convergence Event Instant to the difference from the Convergence Event Instant to the
Convergence Recovery Instant, as shown with Equation 1. Convergence Recovery Instant, as shown with Equation 1.
Equation 1 - Equation 1 -
skipping to change at page 7, line 37 skipping to change at page 8, line 37
Issues: Issues:
None None
See Also: See Also:
Convergence Packet Loss Convergence Packet Loss
Convergence Recovery Instant Convergence Recovery Instant
Convergence Event Instant Convergence Event Instant
Full Convergence Full Convergence
3.9 Convergence Event Transition 3.10 Convergence Event Transition
Definition: Definition:
The characteristic of a router in which Throughput A time interval observed following a Convergence Event in which
gradually reduces to zero after a Convergence Event. Throughput gradually reduces to zero.
Discussion: Discussion:
The Convergence Event Transition is best observed for The Convergence Event Transition is best observed for Full
Full Convergence. The Convergence Event Transition may Convergence. The egress packet rate observed during a
not be linear. Convergence Event Transition may not decrease linearly. Both
the offered load and the Packet Sampling Interval influence the
observations of the Convergence Event Transition. For example,
even if the Convergence Event were to cause the Throughput
[Ba91] to drop to zero there would be some number of packets
observed, unless the Packet Sampling Interval is exactly
aligned with the Convergence Event. This is further discussed
with the term "Packet Sampling Interval".
IGP Data Plane Route Convergence
Measurement Units: Measurement Units:
seconds/milliseconds seconds/milliseconds
Issues: Issues:
None None
See Also: See Also:
Convergence Event Convergence Event
Rate-Derived Convergence Time Full Convergence
Convergence Packet Loss Packet Sampling Interval
Convergence Recovery Transition
IGP Data Plane Route Convergence
3.10 Convergence Recovery Transition 3.11 Convergence Recovery Transition
Definition: Definition:
The characteristic of a router in which Throughput The characteristic of a router in which Throughput
gradually increases to equal the offered load. gradually increases to equal the offered load.
Discussion: Discussion:
The Convergence Recovery Transition is best observed for The Convergence Recovery Transition is best observed for
Full Convergence. The Convergence Event Transition may Full Convergence. The egress packet rate observed during
not be linear. a Convergence Recovery Transition may not increase linearly.
Both the offered load and the Packet Sampling Interval
influence the observations of the Convergence Recovery
Transition. This is further discussed with the term
"Packet Sampling Interval".
Measurement Units: Measurement Units:
seconds/milliseconds seconds/milliseconds
Issues: None Issues: None
See Also: See Also:
Full Convergence Full Convergence
Rate-Derived Convergence Time Packet Sampling Interval
Convergence Packet Loss
Convergence Event Transition
3.11 Loss-Derived Convergence Time 3.12 Loss-Derived Convergence Time
Definition: Definition:
The amount of time it takes for Route Convergence to The amount of time it takes for Route Convergence to
to be achieved as calculated from the Convergence Packet to be achieved as calculated from the Convergence Packet
Loss. Loss-Derived Convergence Time can be calculated Loss. Loss-Derived Convergence Time can be calculated
from Convergence Packet Loss that occurs due to a from Convergence Packet Loss that occurs due to a
Convergence Event and Route Convergence as shown with Convergence Event and Route Convergence as shown with
Equation 2. Equation 2.
Equation 2 - Equation 2 -
Loss-Derived Convergence Time = Loss-Derived Convergence Time =
Convergence Packets Loss / Offered Load Convergence Packets Loss / Offered Load
NOTE: Units for this measurement are NOTE: Units for this measurement are
packets / packets/second = seconds packets / packets/second = seconds
IGP Data Plane Route Convergence
Discussion: Discussion:
Loss-Derived Convergence Time gives a better than Loss-Derived Convergence Time gives a better than
actual result when converging many routes simultaneously. actual result when converging many routes simultaneously.
Rate-Derived Convergence Time takes the Convergence Recovery Rate-Derived Convergence Time takes the Convergence Recovery
Transition into account, but Loss-Derived Convergence Time Transition into account, but Loss-Derived Convergence Time
ignores the Route Convergence Recovery Transition because ignores the Route Convergence Recovery Transition because
it is obtained from the measured Convergence Packet Loss. it is obtained from the measured Convergence Packet Loss.
Ideally, the Convergence Event Transition and Convergence Ideally, the Convergence Event Transition and Convergence
Recovery Transition are instantaneous so that the Recovery Transition are instantaneous so that the
Rate-Derived Convergence Time = Loss-Derived Convergence Time. Rate-Derived Convergence Time = Loss-Derived Convergence Time.
However, router implementations are less than ideal. However, router implementations are less than ideal.
For these reasons the preferred reporting benchmark for IGP For these reasons the preferred reporting benchmark for IGP
Route Convergence is the Rate-Derived Convergence Time. Route Convergence is the Rate-Derived Convergence Time.
IGP Data Plane Route Convergence
Guidelines for reporting Loss-Derived Convergence Time are Guidelines for reporting Loss-Derived Convergence Time are
provided in [Po07m]. provided in [Po07m].
Measurement Units: Measurement Units:
seconds/milliseconds seconds/milliseconds
Issues: Issues:
None None
See Also: See Also:
Route Convergence Convergence Event
Convergence Packet Loss Convergence Packet Loss
Rate-Derived Convergence Time Rate-Derived Convergence Time
Convergence Event Transition Convergence Event Transition
Convergence Recovery Transition Convergence Recovery Transition
3.12 Sustained Forwarding Convergence Time 3.13 Sustained Forwarding Convergence Time
Definition: Definition:
The amount of time for which Full Convergence is maintained The amount of time for which Full Convergence is maintained
without additional packet loss. without additional packet loss.
Discussion: Discussion:
The purpose of the Sustained Forwarding Convergence Time is to The purpose of the Sustained Forwarding Convergence Time is to
produce Convergence benchmarks protected against fluctuation produce Convergence benchmarks protected against fluctuation
in Throughput after Full Convergence is observed. The in Throughput after Full Convergence is observed. The
Sustained Forwarding Convergence Time to be used is calculated Sustained Forwarding Convergence Time to be used is calculated
as shown in Equation 3. as shown in Equation 3.
IGP Data Plane Route Convergence
Equation 3 - Equation 3 -
Sustained Forwarding Convergence Time = Sustained Forwarding Convergence Time =
5*(Convergence Packet Loss/Offered Load) C*(Convergence Packet Loss/Offered Load)
units are packets/pps = sec
for which at least one packet per route in the FIB for all where,
a. units are packets/pps = sec and
b. C is a constant. The RECOMMENDED value for C is 5 as
selected from working group consensus. The value 5 was
obtained from RFC 2544 [Ba99] which uses 5 seconds as the
recommended time for residual frames and DUT restabilization.
c. at least one packet per route in the FIB for all
routes in the FIB MUST be offered to the DUT per second. routes in the FIB MUST be offered to the DUT per second.
Measurement Units: Measurement Units:
seconds or milliseconds seconds or milliseconds
Issues: None Issues: None
See Also: See Also:
Full Convergence Full Convergence
Convergence Recovery Instant Convergence Recovery Instant
3.13 Restoration Convergence Time 3.14 Restoration Convergence Time
Definition: Definition:
The amount of time for the router under test to restore The amount of time for the router under test to restore
traffic to the original outbound port after recovery from traffic to the original outbound port after recovery from
a Convergence Event. a Convergence Event.
IGP Data Plane Route Convergence
Discussion: Discussion:
Restoration Convergence Time is the amount of time for routes Restoration Convergence Time is the amount of time for routes
to converge to the original outbound port. This is achieved to converge to the original outbound port. This is achieved
by recovering from the Convergence Event, such as restoring by recovering from the Convergence Event, such as restoring
the failed link. Restoration Convergence Time is measured the failed link. Restoration Convergence Time is measured
using the Rate-Derived Convergence Time calculation technique, using the Rate-Derived Convergence Time calculation technique,
as provided in Equation 1. It is possible to have the as provided in Equation 1. It is possible to have the
Restoration Convergence Time differ from the Rate-Derived Restoration Convergence Time differ from the Rate-Derived
Convergence Time. Convergence Time.
Measurement Units: Measurement Units:
seconds or milliseconds seconds or milliseconds
Issues: Issues:
None None
See Also: See Also:
Convergence Event Convergence Event
Rate-Derived Convergence Time Rate-Derived Convergence Time
IGP Data Plane Route Convergence
3.15 Packet Sampling Interval
3.14 Packet Sampling Interval
Definition: Definition:
The interval at which the tester (test equipment) polls to make The interval at which the tester (test equipment) polls to make
measurements for arriving packet flows. measurements for arriving packet flows.
Discussion: Discussion:
Metrics measured at the Packet Sampling Interval MUST include Metrics measured at the Packet Sampling Interval MUST include
Forwarding Rate and Convergence Packet Loss. Forwarding Rate and Convergence Packet Loss.
Measurement Units: Measurement Units:
seconds or milliseconds seconds or milliseconds
skipping to change at page 11, line 4 skipping to change at page 12, line 33
Transition and Convergence Recovery Transition can become Transition and Convergence Recovery Transition can become
exaggerated when the Packet Sampling Interval is too long. exaggerated when the Packet Sampling Interval is too long.
This will produce a larger than actual Rate-Derived This will produce a larger than actual Rate-Derived
Convergence Time. The recommended value for configuration Convergence Time. The recommended value for configuration
of the Packet Sampling Interval is provided in [Po07m]. of the Packet Sampling Interval is provided in [Po07m].
See Also: See Also:
Convergence Packet Loss Convergence Packet Loss
Convergence Event Transition Convergence Event Transition
Convergence Recovery Transition Convergence Recovery Transition
IGP Data Plane Route Convergence
3.15 Local Interface 3.16 Local Interface
Definition: Definition:
An interface on the DUT. An interface on the DUT.
Discussion: Discussion:
None None
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Neighbor Interface Neighbor Interface
Remote Interface Remote Interface
IGP Data Plane Route Convergence
3.16 Neighbor Interface 3.17 Neighbor Interface
Definition: Definition:
The interface on the neighbor router or tester that is The interface on the neighbor router or tester that is
directly linked to the DUT's Local Interface. directly linked to the DUT's Local Interface.
Discussion: Discussion:
None None
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Local Interface Local Interface
Remote Interface Remote Interface
3.17 Remote Interface 3.18 Remote Interface
Definition: Definition:
An interface on a neighboring router that is not directly An interface on a neighboring router that is not directly
connected to any interface on the DUT. connected to any interface on the DUT.
Discussion: Discussion:
None None
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
IGP Data Plane Route Convergence
See Also: See Also:
Local Interface Local Interface
Neighbor Interface Neighbor Interface
3.18 Preferred Egress Interface 3.19 Preferred Egress Interface
Definition: Definition:
The outbound interface from the DUT for traffic routed to the The outbound interface from the DUT for traffic routed to the
preferred next-hop. preferred next-hop.
Discussion: Discussion:
The Preferred Egress Interface is the egress interface prior The Preferred Egress Interface is the egress interface prior
to a Convergence Event. to a Convergence Event.
IGP Data Plane Route Convergence
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Next-Best Egress Interface Next-Best Egress Interface
3.19 Next-Best Egress Interface 3.20 Next-Best Egress Interface
Definition: Definition:
The outbound interface from the DUT for traffic routed to the The outbound interface from the DUT for traffic routed to the
second-best next-hop. It is the same media type and link speed second-best next-hop. It is the same media type and link speed
as the Preferred Egress Interface as the Preferred Egress Interface
Discussion: Discussion:
The Next-Best Egress Interface becomes the egress interface The Next-Best Egress Interface becomes the egress interface
after a Convergence Event. after a Convergence Event.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Preferred Egress Interface Preferred Egress Interface
IGP Data Plane Route Convergence
3.20 Stale Forwarding 3.21 Stale Forwarding
Definition: Definition:
Forwarding of traffic to route entries that no longer exist Forwarding of traffic to route entries that no longer exist
or to route entries with next-hops that are no longer preferred. or to route entries with next-hops that are no longer preferred.
Discussion: Discussion:
Stale Forwarding can be caused by a Convergence Event and is Stale Forwarding can be caused by a Convergence Event and is
also known as a "black-hole" since it may produce packet loss. also known as a "black-hole" since it may produce packet loss.
Stale Forwarding exists until Network Convergence is achieved. Stale Forwarding exists until Network Convergence is achieved.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Network Convergence Network Convergence
IGP Data Plane Route Convergence
3.21 Nested Convergence Events 3.22 Nested Convergence Events
Definition: Definition:
The occurrence of a Convergence Event while the route The occurrence of a Convergence Event while the route
table is converging from a prior Convergence Event. table is converging from a prior Convergence Event.
Discussion: Discussion:
The Convergence Events for a Nested Convergence Event The Convergence Events for a Nested Convergence Event
MUST occur with different neighbors. A common MUST occur with different neighbors. A common
observation from a Nested Convergence Event will be observation from a Nested Convergence Event will be
the withdrawal of routes from one neighbor while the the withdrawal of routes from one neighbor while the
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Issues: Issues:
None None
See Also: See Also:
Convergence Event Convergence Event
4. IANA Considerations 4. IANA Considerations
This document requires no IANA considerations. This document requires no IANA considerations.
IGP Data Plane Route Convergence
5. Security Considerations 5. Security Considerations
Documents of this type do not directly affect the security of Documents of this type do not directly affect the security of
Internet or corporate networks as long as benchmarking Internet or corporate networks as long as benchmarking
is not performed on devices or systems connected to production is not performed on devices or systems connected to production
networks. networks.
6. Acknowledgements 6. Acknowledgements
Thanks to Sue Hares, Al Morton, Kevin Dubray, and participants of Thanks to Sue Hares, Al Morton, Kevin Dubray, and participants of
the BMWG for their contributions to this work. the BMWG for their contributions to this work.
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7.1 Normative References 7.1 Normative References
[Ba91] Bradner, S. "Benchmarking Terminology for Network [Ba91] Bradner, S. "Benchmarking Terminology for Network
Interconnection Devices", RFC1242, July 1991. Interconnection Devices", RFC1242, July 1991.
[Ba99] Bradner, S. and McQuaid, J., "Benchmarking [Ba99] Bradner, S. and McQuaid, J., "Benchmarking
Methodology for Network Interconnect Devices", Methodology for Network Interconnect Devices",
RFC 2544, March 1999. RFC 2544, March 1999.
[Br97] Bradner, S., "Key words for use in RFCs to Indicate [Br97] Bradner, S., "Key words for use in RFCs to Indicate
IGP Data Plane Route Convergence
[Ca90] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual [Ca90] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual
Environments", RFC 1195, December 1990. Environments", RFC 1195, December 1990.
[Ma98] Mandeville, R., "Benchmarking Terminology for LAN [Ma98] Mandeville, R., "Benchmarking Terminology for LAN
Switching Devices", RFC 2285, February 1998. Switching Devices", RFC 2285, February 1998.
[Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998. [Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.
[Mo06] Morton, A., et al, "Packet Reordering Metrics", RFC 4737,
November 2006.
[Po06] Poretsky, S., et al., "Terminology for Benchmarking
Network-layer Traffic Control Mechanisms", RFC 4689,
November 2006.
[Po07a] Poretsky, S., "Benchmarking Applicability for IGP Data Plane [Po07a] Poretsky, S., "Benchmarking Applicability for IGP Data Plane
Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-12, Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-13,
work in progress, February 2007. work in progress, July 2007.
[Po07m] Poretsky, S., "Benchmarking Methodology for IGP Data Plane [Po07m] Poretsky, S. and Imhoff, B., "Benchmarking Methodology for
Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-12, IGP Data Plane Route Convergence",
work in progress, February 2007. draft-ietf-bmwg-igp-dataplane-conv-meth-13, work in progress,
July 2007.
7.2 Informative References 7.2 Informative References
[Ca01] S. Casner, C. Alaettinoglu, and C. Kuan, "A Fine-Grained View [Ca01] S. Casner, C. Alaettinoglu, and C. Kuan, "A Fine-Grained View
of High Performance Networking", NANOG 22, June 2001. of High Performance Networking", NANOG 22, June 2001.
[Ci03] L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized [Ci03] L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized
Active Measurements on a Tier 1 IP Backbone", IEEE Active Measurements on a Tier 1 IP Backbone", IEEE
Communications Magazine, pp90-97, May 2003. Communications Magazine, pp90-97, May 2003.
IGP Data Plane Route Convergence
8. Author's Address 8. Author's Address
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
8 New England Executive Park 8 New England Executive Park
Burlington, MA 01803 Burlington, MA 01803
USA USA
Phone: + 1 508 439 9008 Phone: + 1 508 439 9008
EMail: sporetsky@reefpoint.com EMail: sporetsky@reefpoint.com
Brent Imhoff Brent Imhoff
Juniper Networks Juniper Networks
1194 North Mathilda Ave 1194 North Mathilda Ave
Sunnyvale, CA 94089 Sunnyvale, CA 94089
USA USA
Phone: + 1 314 378 2571 Phone: + 1 314 378 2571
EMail: bimhoff@planetspork.com EMail: bimhoff@planetspork.com
IGP Data Plane Route Convergence
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided This document and the information contained herein are provided
on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
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IGP Data Plane Route Convergence
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