draft-ietf-grow-bgp-med-considerations-02.txt   draft-ietf-grow-bgp-med-considerations-03.txt 
INTERNET-DRAFT Danny McPherson INTERNET-DRAFT Danny McPherson
Arbor Networks, Inc. Arbor Networks, Inc.
Vijay Gill Vijay Gill
AOL AOL
Category Informational Category Informational
Expires: January 2005 July 2004 Expires: September 2005 March 2005
BGP MED Considerations BGP MED Considerations
<draft-ietf-grow-bgp-med-considerations-02.txt> <draft-ietf-grow-bgp-med-considerations-03.txt>
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2005). All Rights Reserved.
Abstract Abstract
The BGP MED attribute provides a mechanism for BGP speakers to convey The BGP MED attribute provides a mechanism for BGP speakers to convey
to an adjacent AS the optimal entry point into the local AS. While to an adjacent AS the optimal entry point into the local AS. While
BGP MEDs function correctly in many scenarios, there are a number of BGP MEDs function correctly in many scenarios, there are a number of
issues which may arise when utilizing MEDs in dynamic or complex issues which may arise when utilizing MEDs in dynamic or complex
topologies. topologies.
This document discusses implementation and deployment considerations This document discusses implementation and deployment considerations
regarding BGP MEDs and provides information which implementors and regarding BGP MEDs and provides information which implementors and
network operators should be familiar with. network operators should be familiar with.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. About the MULTI_EXIT_DISC (MED) Attribute . . . . . . . . . 4 1.1. About the MULTI_EXIT_DISC (MED) Attribute . . . . . . . . . 4
1.2. MEDs and Potatoes . . . . . . . . . . . . . . . . . . . . . 5 1.2. MEDs and Potatos. . . . . . . . . . . . . . . . . . . . . . 5
2. Implementation and Protocol Considerations . . . . . . . . . . 6 2. Implementation and Protocol Considerations . . . . . . . . . . 6
2.1. MULTI_EXIT_DISC is a Optional Non-Transitive 2.1. MULTI_EXIT_DISC is a Optional Non-Transitive
Attribute. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Attribute. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2. MED Values and Preferences. . . . . . . . . . . . . . . . . 7 2.2. MED Values and Preferences. . . . . . . . . . . . . . . . . 7
2.3. Comparing MEDs Between Different Autonomous 2.3. Comparing MEDs Between Different Autonomous
Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4. MEDs, Route Reflection and AS Confederations 2.4. MEDs, Route Reflection and AS Confederations
for BGP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 for BGP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5. Route Flap Damping and MED Churn. . . . . . . . . . . . . . 9 2.5. Route Flap Damping and MED Churn. . . . . . . . . . . . . . 9
2.6. Effects of MEDs on Update Packing Efficiency. . . . . . . . 9 2.6. Effects of MEDs on Update Packing Efficiency. . . . . . . . 9
2.7. Temporal Route Selection. . . . . . . . . . . . . . . . . . 10 2.7. Temporal Route Selection. . . . . . . . . . . . . . . . . . 10
3. Deployment Considerations. . . . . . . . . . . . . . . . . . . 10 3. Deployment Considerations. . . . . . . . . . . . . . . . . . . 10
3.1. Comparing MEDs Between Different Autonomous 3.1. Comparing MEDs Between Different Autonomous
Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2. Effects of Aggregation on MEDs` . . . . . . . . . . . . . . 11 3.2. Effects of Aggregation on MEDs` . . . . . . . . . . . . . . 11
4. Security Considerations. . . . . . . . . . . . . . . . . . . . 12 4. Security Considerations. . . . . . . . . . . . . . . . . . . . 12
4.1. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 12 4.1. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 12
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13 5.1. Normative References. . . . . . . . . . . . . . . . . . . . 14
7. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 13 5.2. Informative References. . . . . . . . . . . . . . . . . . . 15
6. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
The BGP MED attribute provides a mechanism for BGP speakers to convey The BGP MED attribute provides a mechanism for BGP speakers to convey
to an adjacent AS the optimal entry point into the local AS. While to an adjacent AS the optimal entry point into the local AS. While
BGP MEDs function correctly in many scenarios, there are a number of BGP MEDs function correctly in many scenarios, there are a number of
issues which may arise when utilizing MEDs in dynamic or complex issues which may arise when utilizing MEDs in dynamic or complex
topologies. topologies.
This document discusses implementation and deployment considerations This document discusses implementation and deployment considerations
regarding BGP MEDs and provides information which implementors and regarding BGP MEDs and provides information which implementors and
network operators should be familiar with. network operators should be familiar with.
1.1. About the MULTI_EXIT_DISC (MED) Attribute 1.1. About the MULTI_EXIT_DISC (MED) Attribute
The BGP MUTLI_EXIT_DISC (MED) attribute, formerly known as the The BGP MULTI_EXIT_DISC (MED) attribute, formerly known as the
INTER_AS_METRIC, is currently defined in section 5.1.4 of [BGP4], as INTER_AS_METRIC, is currently defined in section 5.1.4 of [BGP4], as
follows: follows:
MULTI_EXIT_DISC is an optional non-transitive attribute which is The MULTI_EXIT_DISC is an optional non-transitive attribute which
intended to be used on external (inter-AS) links to discriminate is intended to be used on external (inter-AS) links to discriminate
among multiple exit or entry points to the same neighboring AS. among multiple exit or entry points to the same neighboring AS.
The MULTI_EXIT_DISC attribute is a four octet unsigned number which The value of the MULTI_EXIT_DISC attribute is a four octet unsigned
is called a metric. All other factors being equal, the exit point number which is called a metric. All other factors being equal, the
with lower metric SHOULD be preferred. If received over EBGP, the exit point with lower metric SHOULD be preferred. If received over
MULTI_EXIT_DISC attribute MAY be propagated over IBGP to other BGP EBGP, the MULTI_EXIT_DISC attribute MAY be propagated over IBGP to
speakers within the same AS. An MED attribute received from a other BGP speakers within the same AS (see also 9.1.2.2). The
neighboring AS MUST NOT be propagated to other neighboring MULTI_EXIT_DISC attribute received from a neighboring AS MUST NOT
autonomous systems. be propagated to other neighboring ASs.
A BGP speaker MUST IMPLEMENT a mechanism based on local A BGP speaker MUST implement a mechanism based on local
configuration which allows the MULTI_EXIT_DISC attribute to be configuration which allows the MULTI_EXIT_DISC attribute to be
removed from a route. This MAY be done prior to determining the removed from a route. If a BGP speaker is configured to remove the
degree of preference of the route and performing route selection MULTI_EXIT_DISC attribute from a route, then this removal MUST be
(decision process phases 1 and 2). done prior to determining the degree of preference of the route and
performing route selection (Decision Process phases 1 and 2).
An implementation MAY also (based on local configuration) alter the An implementation MAY also (based on local configuration) alter the
value of the MULTI_EXIT_DISC attribute received over EBGP. This value of the MULTI_EXIT_DISC attribute received over EBGP. If a
MAY be done prior to determining the degree of preference of the BGP speaker is configured to alter the value of the MULTI_EXIT_DISC
route and performing route selection (decision process phases 1 and attribute received over EBGP, then altering the value MUST be done
2). prior to determining the degree of preference of the route and
performing route selection (Decision Process phases 1 and 2). See
Section 9.1.2.2 of BGP4] for necessary restrictions on this.
Section 9.1.2.2 (c) of [BGP4] defines the following route selection Section 9.1.2.2 (c) of [BGP4] defines the following route selection
criteria regarding MEDs: criteria regarding MEDs:
Remove from consideration routes with less-preferred c) Remove from consideration routes with less-preferred
MULTI_EXIT_DISC attributes. MULTI_EXIT_DISC is only comparable MULTI_EXIT_DISC attributes. MULTI_EXIT_DISC is only comparable
between routes learned from the same neighboring AS (the between routes learned from the same neighboring AS (the neighbor-
neighboring AS is determined from the AS_PATH attribute). Routes ing AS is determined from the AS_PATH attribute). Routes which do
which do not have the MULTI_EXIT_DISC attribute are considered to not have the MULTI_EXIT_DISC attribute are considered to have the
have the lowest possible MULTI_EXIT_DISC value. lowest possible MULTI_EXIT_DISC value.
This is also described in the following procedure: This is also described in the following procedure:
for m = all routes still under consideration for m = all routes still under consideration
for n = all routes still under consideration for n = all routes still under consideration
if (neighborAS(m) == neighborAS(n)) and (MED(n) < MED(m)) if (neighborAS(m) == neighborAS(n)) and (MED(n) < MED(m))
remove route m from consideration remove route m from consideration
In the pseudo-code above, MED(n) is a function which returns the In the pseudo-code above, MED(n) is a function which returns the
value of route n's MULTI_EXIT_DISC attribute. If route n has no value of route n's MULTI_EXIT_DISC attribute. If route n has no
MULTI_EXIT_DISC attribute, the function returns the lowest possible MULTI_EXIT_DISC attribute, the function returns the lowest possi-
MULTI_EXIT_DISC value, i.e. 0. ble MULTI_EXIT_DISC value, i.e. 0.
If a MULTI_EXIT_DISC attribute is removed before re- advertising a If a MULTI_EXIT_DISC attribute is removed before re- advertising a
route into IBGP, then comparison based on the received EBGP route into IBGP, then comparison based on the received EBGP
MULTI_EXIT_DISC attribute MAY still be performed. If an MULTI_EXIT_DISC attribute MAY still be performed. If an
implementation chooses to remove MULTI_EXIT_DISC, then the optional implementation chooses to remove MULTI_EXIT_DISC, then the optional
comparison on MULTI_EXIT_DISC if performed at all MUST be performed comparison on MULTI_EXIT_DISC if performed at all MUST be performed
only among EBGP learned routes. The best EBGP learned route may only among EBGP learned routes. The best EBGP learned route may
then be compared with IBGP learned routes after the removal of the then be compared with IBGP learned routes after the removal of the
MULTI_EXIT_DISC attribute. If MULTI_EXIT_DISC is removed from a MULTI_EXIT_DISC attribute. If MULTI_EXIT_DISC is removed from a
subset of EBGP learned routes and the selected "best" EBGP learned subset of EBGP learned routes and the selected "best" EBGP learned
route will not have MULTI_EXIT_DISC removed, then the route will not have MULTI_EXIT_DISC removed, then the
MULTI_EXIT_DISC must be used in the comparison with IBGP learned MULTI_EXIT_DISC must be used in the comparison with IBGP learned
routes. For IBGP learned routes the MULTI_EXIT_DISC MUST be used in routes. For IBGP learned routes the MULTI_EXIT_DISC MUST be used in
route comparisons which reach this step in the decision process. route comparisons which reach this step in the Decision Process.
Including the MULTI_EXIT_DISC of an EBGP learned route in the Including the MULTI_EXIT_DISC of an EBGP learned route in the
comparison with an IBGP learned route, then removing the comparison with an IBGP learned route, then removing the
MULTI_EXIT_DISC attribute and advertising the route has been proven MULTI_EXIT_DISC attribute and advertising the route has been proven
to cause route loops. to cause route loops.
Routes that have different MULTI_EXIT_DISC attribute SHALL NOT be 1.2. MEDs and Potatos
aggregated.
1.2. MEDs and Potatoes
In a situation where traffic flows between a pair of hosts, each In a situation where traffic flows between a pair of hosts, each
connected to different transit networks, which are themselves connected to different transit networks, which are themselves
interconnected at two or more locations, each transit network has the interconnected at two or more locations, each transit network has the
choice of either sending traffic to the closest peering to the choice of either sending traffic to the closest peering to the
adjacent transit network or passing traffic to the interconnection adjacent transit network or passing traffic to the interconnection
location which advertises the least cost path to the destination location which advertises the least cost path to the destination
host. host.
The former method is called "hot potato routing" (or closest-exit) The former method is called "hot potato routing" (or closest-exit)
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In some cases a provider may use hot potato routing for some In some cases a provider may use hot potato routing for some
destinations for a given peer AS and cold potato routing for others. destinations for a given peer AS and cold potato routing for others.
An example of this is the different treatment of commercial and An example of this is the different treatment of commercial and
research traffic in the NSFNET in the mid 1990s. Today many research traffic in the NSFNET in the mid 1990s. Today many
commercial networks exchange MEDs with customers but not bilateral commercial networks exchange MEDs with customers but not bilateral
peers. However, commercial use of MEDs varies widely, from peers. However, commercial use of MEDs varies widely, from
ubiquitous use of MEDs to no use of MEDs at all. ubiquitous use of MEDs to no use of MEDs at all.
In addition, many deployments of MEDs today are likely behaving In addition, many deployments of MEDs today are likely behaving
differently (e.g., resulting is sub-optimal routing) than the network differently (e.g., resulting is sub-optimal routing) than the network
operator intended, thereby resulting not in hot or cold potatoes, but operator intended, thereby resulting not in hot or cold potatos, but
mashed potatoes! More information on unintended behavior resulting mashed potatos! More information on unintended behavior resulting
from MEDs is provided throughout this document. from MEDs is provided throughout this document.
2. Implementation and Protocol Considerations 2. Implementation and Protocol Considerations
There are a number of implementation and protocol peculiarities There are a number of implementation and protocol peculiarities
relating to MEDs that have been discovered that may affect network relating to MEDs that have been discovered that may affect network
behavior. The following sections provide information on these behavior. The following sections provide information on these
issues. issues.
2.1. MULTI_EXIT_DISC is a Optional Non-Transitive Attribute 2.1. MULTI_EXIT_DISC is a Optional Non-Transitive Attribute
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Given current practices, we see the problem most frequently manifest Given current practices, we see the problem most frequently manifest
itself in the context of MED + route reflectors or confederations. itself in the context of MED + route reflectors or confederations.
One potential way to avoid this is by configuring inter-Member-AS or One potential way to avoid this is by configuring inter-Member-AS or
inter-cluster IGP metrics higher than intra-Member-AS IGP metrics inter-cluster IGP metrics higher than intra-Member-AS IGP metrics
and/or using other tie breaking policies to avoid BGP route selection and/or using other tie breaking policies to avoid BGP route selection
based on incomparable MEDs. Of course, IGP metric constraints may be based on incomparable MEDs. Of course, IGP metric constraints may be
unreasonably onerous for some applications. unreasonably onerous for some applications.
Comparing MEDs between differing adjacent autonomous systems (which Comparing MEDs between differing adjacent autonomous systems (which
will be discussed in later sections), or not utilizing MEDs at all, is discussed in other sections), or not utilizing MEDs at all,
significantly decreases the probability of introducing potential significantly decreases the probability of introducing potential
route oscillation conditions into the network. route oscillation conditions into the network.
Although perhaps "legal" as far as current specifications are Although perhaps "legal" as far as current specifications are
concerned, modifying MED attributes received on any type of IBGP concerned, modifying MED attributes received on any type of IBGP
session (e.g., standard IBGP, AS confederations EIBGP, route session (e.g., standard IBGP, AS confederations EIBGP, route
reflection, etc..) is NOT recommended. reflection, etc..) is NOT recommended.
2.5. Route Flap Damping and MED Churn 2.5. Route Flap Damping and MED Churn
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Many implementations don't have a practical problem with IGP Many implementations don't have a practical problem with IGP
flapping, they either latch their IGP metric upon first advertisement flapping, they either latch their IGP metric upon first advertisement
or they employ some internal suppression mechanism. Some or they employ some internal suppression mechanism. Some
implementations regard BGP attribute changes as less significant than implementations regard BGP attribute changes as less significant than
route withdrawals and announcements to attempt to mitigate the impact route withdrawals and announcements to attempt to mitigate the impact
of this type of event. of this type of event.
2.6. Effects of MEDs on Update Packing Efficiency 2.6. Effects of MEDs on Update Packing Efficiency
Multiple unfeasible routes can be advertised in a single BGP Update Multiple unfeasible routes can be advertised in a single BGP Update
message. In addition, one or more feasible routes can be advertised message. The BGP4 protocol also permits advertisement of multiple
in a single Update message so long as all prefixes share a common prefixes with a common set of path attributes to be advertised in a
attribute set. single update message, this is commonly referred to as "update
packing". When possible, update packing is recommended as it
The BGP4 protocol permits advertisement of multiple prefixes with a provides a mechanism for more efficient behavior in a number of
common set of path attributes to be advertised in a single update areas, to include:
message, this is commonly referred to as "update packing". When
possible, update packing is recommended as it provides a mechanism
for more efficient behavior in a number of areas, to include:
o Reduction in system overhead due to generation or receipt of o Reduction in system overhead due to generation or receipt of
fewer Update messages. fewer Update messages.
o Reduction in network overhead as a result of fewer packets and o Reduction in network overhead as a result of fewer packets and
lower bandwidth consumption. lower bandwidth consumption.
o Allows processing of path attributes and searches for matching o Allows processing of path attributes and searches for matching
sets in your AS_PATH database (if you have one) less frequently. sets in your AS_PATH database (if you have one) less frequently.
Consistent ordering of the path attributes allows for ease of Consistent ordering of the path attributes allows for ease of
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earlier implementations that cause non-deterministic behavior on earlier implementations that cause non-deterministic behavior on
whether the oldest route would truly be selected or not. whether the oldest route would truly be selected or not.
The reasoning for this is that "older" paths are presumably more The reasoning for this is that "older" paths are presumably more
stable, and thus more preferable. However, temporal behavior in stable, and thus more preferable. However, temporal behavior in
route selection results in non-deterministic behavior, and as such, route selection results in non-deterministic behavior, and as such,
is often undesirable. is often undesirable.
3. Deployment Considerations 3. Deployment Considerations
Empirical data [MFN/Ixia Monitoring Project] has shown that accepting It has been discussed that accepting MEDs from other autonomous
MEDs from other autonomous systems have the potential to cause systems have the potential to cause traffic flow churns in the
traffic flow churns in the network. Some implementations only network. Some implementations only ratchet down the MED and never
ratchet down the MED and never move it back up to prevent excessive move it back up to prevent excessive churn.
churn.
However, if that session is reset, the MEDs being advertised have the However, if a session is reset, the MEDs being advertised have the
potential of changing. If an network is relying on received MEDs to potential of changing. If an network is relying on received MEDs to
route traffic properly, the traffic patterns have the potential for route traffic properly, the traffic patterns have the potential for
changing dramatically, potentially resulting in congestion on the changing dramatically, potentially resulting in congestion on the
network. Essentially, accepting and routing traffic based on MEDs network. Essentially, accepting and routing traffic based on MEDs
allows other people to traffic engineer your network. This may or may allows other people to traffic engineer your network. This may or may
not be acceptable to you. not be acceptable to you.
As previously discussed, many network operators choose to reset MED As previously discussed, many network operators choose to reset MED
values on ingress. In addition, many operators explicitly do not values on ingress. In addition, many operators explicitly do not
employ MED values of 0 or 2^32-1 in order to avoid inconsistencies employ MED values of 0 or 2^32-1 in order to avoid inconsistencies
with implementations and various revisions of the BGP specification. with implementations and various revisions of the BGP specification.
3.1. Comparing MEDs Between Different Autonomous Systems 3.1. Comparing MEDs Between Different Autonomous Systems
Although the MED was meant to only be used when comparing paths Although the MED was meant to only be used when comparing paths
received from different external peers in the same AS, many received from different external peers in the same AS, many
implementations provide the capability to compare MEDs between implementations provide the capability to compare MEDs between
different autonomous systems as well. different autonomous systems as well. AS operators often use
LOCAL_PREF to select the external preferences (primary, secondary
upstreams, peers, customers, etc.), using MED instead of LOCAL_PREF
would possibility lead to an inconsistent distribution of best routes
as MED is compared only after the AS_PATH length.
Though this may seem a fine idea for some configurations, care must Though this may seem a fine idea for some configurations, care must
be taken when comparing MEDs between different autonomous systems. be taken when comparing MEDs between different autonomous systems.
BGP speakers often derive MED values by obtaining the IGP metric BGP speakers often derive MED values by obtaining the IGP metric
associated with reaching a given BGP NEXT_HOP within the local AS. associated with reaching a given BGP NEXT_HOP within the local AS.
This allows MEDs to reasonably reflect IGP topologies when This allows MEDs to reasonably reflect IGP topologies when
advertising routes to peers. While this is fine when comparing MEDs advertising routes to peers. While this is fine when comparing MEDs
between multiple paths learned from a single AS, it can result in between multiple paths learned from a single AS, it can result in
potentially "weighted" decisions when comparing MEDs between potentially "weighted" decisions when comparing MEDs between
different autonomous systems. This is most typically the case when different autonomous systems. This is most typically the case when
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group was concerned that any metric specified by a remote operator group was concerned that any metric specified by a remote operator
would only affect routing in a local AS IF no other preference was would only affect routing in a local AS IF no other preference was
specified. A paramount goal of the design of the MED was to ensure specified. A paramount goal of the design of the MED was to ensure
that peers could not "shed" or "absorb" traffic for networks that that peers could not "shed" or "absorb" traffic for networks that
they advertise. As such, accepting MEDs from peers may in some sense they advertise. As such, accepting MEDs from peers may in some sense
increase a network's susceptibility to exploitation by peers. increase a network's susceptibility to exploitation by peers.
4.1. Acknowledgments 4.1. Acknowledgments
Thanks to John Scudder for applying his usual keen eye and Thanks to John Scudder for applying his usual keen eye and
constructive insight. Also, thanks to Curtis Villamizar and JR constructive insight. Also, thanks to Curtis Villamizar, JR Mitchell
Mitchell. and Pekka Savola for their valuable feedback.
Others to be supplied.
5. References 5. References
5.1. Normative References
[RFC 1519] Fuller, V., Li. T., Yu J., and K. Varadhan, "Classless [RFC 1519] Fuller, V., Li. T., Yu J., and K. Varadhan, "Classless
Inter-Domain Routing (CIDR): an Address Assignment and Inter-Domain Routing (CIDR): an Address Assignment and
Aggregation Strategy", RFC 1519, September 1993. Aggregation Strategy", RFC 1519, September 1993.
[RFC 1771] Rekhter, Y., and T. Li, "A Border Gateway Protocol 4 [RFC 1771] Rekhter, Y., and T. Li, "A Border Gateway Protocol 4
(BGP-4)", RFC 1771, March 1995. (BGP-4)", RFC 1771, March 1995.
[RFC 2439] Villamizar, C. and Chandra, R., "BGP Route Flap Damping",
RFC 2439, November 1998.
[RFC 2796] Bates, T., Chandra, R., Chen, E., "BGP Route Reflection [RFC 2796] Bates, T., Chandra, R., Chen, E., "BGP Route Reflection
- An Alternative to Full Mesh IBGP", RFC 2796, April - An Alternative to Full Mesh IBGP", RFC 2796, April
2000. 2000.
[RFC 3065] Traina, P., McPherson, D., Scudder, J.. "Autonomous System [RFC 3065] Traina, P., McPherson, D., Scudder, J.. "Autonomous System
Confederations for BGP", RFC 3065, February 2001. Confederations for BGP", RFC 3065, February 2001.
[RFC 3345] McPherson, D., Gill, V., Walton, D., and Retana, A, "BGP
Persistent Route Oscillation Condition", RFC 3345,
August 2002.
[BGP4] Rekhter, Y., T. Li., and Hares. S, Editors, "A Border [BGP4] Rekhter, Y., T. Li., and Hares. S, Editors, "A Border
Gateway Protocol 4 (BGP-4)", BGP Draft, Work in Progress. Gateway Protocol 4 (BGP-4)", BGP Draft, Work in Progress.
[MFN/Ixia Monitoring Project] Vijay to Provide Pointer. 5.2. Informative References
[RFC 2439] Villamizar, C. and Chandra, R., "BGP Route Flap Damping",
RFC 2439, November 1998.
[RFC 3345] McPherson, D., Gill, V., Walton, D., and Retana, A, "BGP
Persistent Route Oscillation Condition", RFC 3345,
August 2002.
6. Authors' Addresses 6. Authors' Addresses
Danny McPherson Danny McPherson
Arbor Networks Arbor Networks
Email: danny@arbor.net Email: danny@arbor.net
Vijay Gill Vijay Gill
AOL AOL
Email: VijayGill9@aol.com Email: VijayGill9@aol.com
7. Full Copyright Statement Intellectual Property Statement
Copyright (C) The Internet Society (2004). All Rights Reserved. The IETF takes no position regarding the validity or scope of any
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