Internet DRAFT - draft-parise-bmwg-ldp-convergence-term
draft-parise-bmwg-ldp-convergence-term
Benchmarking Working Group B. Parise
Internet-Draft Cisco Systems
Intended status: Standards Track R. Papneja
Expires: January 4, 2014 Huawei Technologies
July 3, 2013
Terminology for Benchmarking LDP Data Plane Convergence
draft-parise-bmwg-ldp-convergence-term-00.txt
Abstract
This document defines new terms for benchmarking of LDP convergence.
These terms are to be used in future methodology documents for
benchmarking LDP Convergence. Existing BMWG terminology documents
such as IGP Convergence Benchmarking [RFC 6412] provide useful terms
for LDP Convergence benchmarking. These terms are discussed in this
document. Applicable terminology for MPLS and LDP defined in MPLS WG
RFCs [RFC 3031] and [RFC 5036] are also discussed.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Existing Definitions . . . . . . . . . . . . . . . . . . . . . 4
2.1. BMWG Convergence Terms . . . . . . . . . . . . . . . . . . 4
2.2. MPLS/LDP Terms . . . . . . . . . . . . . . . . . . . . . . 4
3. Term Definitions . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. LDP Binding Table . . . . . . . . . . . . . . . . . . . . 5
3.2. FEC Forwarding Table . . . . . . . . . . . . . . . . . . . 6
3.3. FEC Convergence Event . . . . . . . . . . . . . . . . . . 6
3.4. FEC Forwarding Table Convergence . . . . . . . . . . . . . 7
3.5. FEC Convergence . . . . . . . . . . . . . . . . . . . . . 7
3.6. Multiple Next-Hop FEC . . . . . . . . . . . . . . . . . . 8
3.7. Ingress LSR . . . . . . . . . . . . . . . . . . . . . . . 9
3.8. Egress LSR . . . . . . . . . . . . . . . . . . . . . . . . 9
3.9. LDP Peer . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.10. Targeted LDP Peer . . . . . . . . . . . . . . . . . . . . 11
3.11. Targeted FECs . . . . . . . . . . . . . . . . . . . . . . 11
3.12. Multi-Labeled Packets . . . . . . . . . . . . . . . . . . 12
3.13. Equal Cost Multiple Paths . . . . . . . . . . . . . . . . 12
3.14. Equal Cost Multiple FECs . . . . . . . . . . . . . . . . . 13
3.15. FEC Convergence at Ingress LSR . . . . . . . . . . . . . . 13
3.16. FEC Convergence at Midpoint LSR . . . . . . . . . . . . . 14
3.17. LDP Advertisement Type . . . . . . . . . . . . . . . . . . 14
3.18. Label Merging LSR . . . . . . . . . . . . . . . . . . . . 15
3.19. Non-merging LSR . . . . . . . . . . . . . . . . . . . . . 16
3.20. LDPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4. Factors impacting Convergence . . . . . . . . . . . . . . . . 17
4.1. Interaction with Other Protocols . . . . . . . . . . . . . 17
4.2. Timers . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.3. TCP Parameters . . . . . . . . . . . . . . . . . . . . . . 17
5. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.1. Normative References . . . . . . . . . . . . . . . . . . . 18
7.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
This draft describes the terminology for benchmarking LDP
Convergence. An accompanying document will describe the methodology
for doing the benchmarking. The main motivation for doing this work
is the increased focus on lowering convergence time for LDP as an
alternative to other solutions such as MPLS Fast Reroute (i.e.
protection techniques using RSVP-TE extensions).
The purpose of this document is to find existing terminology as well
as define new terminology when needed terms are not available. The
terminology will support the methodology that will be based on black-
box testing of the LDP dataplane. The approach is very similar to
the one found in [RFC 6412] and [RFC 6413].
2. Existing Definitions
2.1. BMWG Convergence Terms
This document uses existing terminology defined in other IETF
documents. These include the following:
Route Convergence Defined in [RFC 6412]
Convergence Packet Loss Defined in [RFC 6412]
Convergence Event Instant Defined in [RFC 6412]
Convergence Recovery Instant Defined in [RFC 6412]
Rate-Derived Convergence Time Defined in [RFC 6412]
Convergence Event Transition Defined in [RFC 6412]
Convergence Recovery Transition Defined in [RFC 6412]
Loss-Derived Convergence Time Defined in [RFC 6412]
Restoration Convergence Time Defined in [RFC 6412]
Packet Sampling Interval Defined in [RFC 6412]
Local Interface Defined in [RFC 6412]
Neighbor Interface Defined in [RFC 6412]
Remote Interface Defined in [RFC 6412]
Preferred Egress Interface Defined in [RFC 6412]
Next-Best Egress Interface Defined in [RFC 6412]
Stale Forwarding Defined in [RFC 6412]
2.2. MPLS/LDP Terms
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Label Defined in [RFC 3031]
FEC Defined in [RFC 3031]
Label Withdraw Defined in [RFC 5036]
LSP Defined in [RFC 3031]
LSR Defined in [RFC 3031]
LDP Identifier Defined in [RFC 5036]
LDP Session Defined in [RFC 5036]
Per-Interface Label Space Defined in [RFC 3031]
Per-Platform Label Space Defined in [RFC 3031]
MPLS Node Defined in [RFC 3031]
MPLS Edge Node Defined in [RFC 3031]
MPLS Egress Node Defined in [RFC 3031]
MPLS Ingress Node Defined in [RFC 3031]
Upstream LSR Defined in [RFC 3031]
Downstream LSR Defined in [RFC 3031]
Local Repair Defined in [RFC 4090]
PLR Defined in [RFC 4090]
One-to-One Backup Defined in [RFC 4090]
Detour LSP Defined in [RFC 4090]
Backup Path Defined in [RFC 4090]
Downstream-on-Demand Defined in [RFC 3031]
Unsolicited Downstream Defined in [RFC 3031]
Independent Label Distribution Control
Defined in [RFC 5036]
Address Family Defined in [RFC 5036]
IGP Update Message ISIS/OSPF LSA
3. Term Definitions
3.1. LDP Binding Table
Definition:
Table in which the LSR maintains all learned labels. It consists
of the prefix and label information bound to a peer's LDP
identifier and the list of sent and received bindings/peer.
Discussion:
None
Measurement Units:
N/A
Issues:
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None
See Also:
FEC Forwarding Table
3.2. FEC Forwarding Table
Definition:
Table in which the LSR maintains the next hop information for the
particular FEC with the associated outgoing label and interface.
The information used for setting up the FEC forwarding table is
retrieved from the LDP Binding Table.
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
LDP Binding Table
3.3. FEC Convergence Event
Definition:
The occurrence of a planned or unplanned action in the network
that results in a change to an LSR's LDP next-hop forwarding.
Discussion:
Convergence Events include link loss, routing protocol session
loss, router failure, and better next-hop. Also, different types
of administrative events such as interface shutdown is considered.
Measurement Units:
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N/A
Issues:
None
See Also:
FEC Forwarding Table Convergence
FEC Convergence
3.4. FEC Forwarding Table Convergence
Definition:
Recovery from a FEC Convergence Event that causes the FEC
Forwarding Table to change and re-stabilize.
Discussion:
FEC Forwarding Table Convergence updates after the RIB and LDP
Binding Table update due to a FEC Convergence Event. FEC
Forwarding Table Convergence can be observed externally by the
rerouting of data Traffic to a new egress interface.
Measurement Units:
seconds
Issues:
None
See Also:
FEC Forwarding Table
FEC Convergence Event
FEC Convergence
3.5. FEC Convergence
Definition:
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Recovery from a FEC Convergence Event that causes the LDP Binding
Table to change and re-stabilize.
Discussion:
FEC Convergence is a change in an LDP Binding of a prefix and
label to a peer's LDP Identifier. This change can be an update or
recovery due to a FEC Convergence Event. FEC Convergence is an
LSR action made prior to FEC Forwarding Table Convergence. FEC
Convergence is not an externally observable Black-Box measurement.
Measurement Units:
N/A
Issues:
Where is LDP Identifier defined? Where is LDP Binding defined?
See Also:
FEC Binding Table
FEC Convergence Event
FEC Forwarding Table Convergence
3.6. Multiple Next-Hop FEC
Definition:
A FEC with more than one next-hop and associated outgoing label
and interface.
Discussion:
A Multiple Next-Hop FEC can be verified from the FEC Forwarding
Table and from externally observing traffic being forwarded to a
FEC on one or more interfaces.
Measurement Units:
N/A
Issues:
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None
See Also:
FEC Forwarding Table
3.7. Ingress LSR
Definition:
An MPLS ingress node which is capable of forwarding native L3
packets.
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
MPLS Node
MPLS Edge Node
MPLS Egress Node
MPLS Ingress Node
Label Switching Router (LSR)
Egress LSR
3.8. Egress LSR
Definition:
An MPLS Egress node which is capable of forwarding native L3
packets.
Discussion:
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None
Measurement Units:
N/A
Issues:
None
See Also:
MPLS Node
MPLS Edge Node
MPLS Egress Node
MPLS Ingress Node
Label Switching Router (LSR)
Ingress LSR
3.9. LDP Peer
Definition:
An adjacent LSR with which LDP adjacency is established
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
Targeted LDP Peer
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3.10. Targeted LDP Peer
Definition:
An adjacent LSR (usually more than a hop away) with which LDP
adjacency is established through a directed hello message which is
unicast.
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
LDP Peer
3.11. Targeted FECs
Definition:
The FECs advertised by a Targeted LDP Peer
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
Targeted Peer
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3.12. Multi-Labeled Packets
Definition:
A data packet that has more than one label in the label stack.
Discussion:
This typically happens when a Targeted Peer is established over a
traffic engineered tunnel.
Measurement Units:
N/A
Issues:
None
See Also:
None
3.13. Equal Cost Multiple Paths
Definition:
Existence of multiple IGP paths to reach a particular destination.
In this case the depending on the implementation traffic destined
to a prefix that has multiple equal cost paths is load balanced
across all these paths.
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
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Equal Cost Multiple FECs
3.14. Equal Cost Multiple FECs
Definition:
Existence of multiple to reach a destination. Typically the LSR
that has multiple FECs of equal costs does a load balance on all
the FECs
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
Equal Cost Multiple Paths
3.15. FEC Convergence at Ingress LSR
Definition:
Recovery from a FEC Convergence Event that causes the LDP Binding
Table to change and re-stabilize at the Ingress LSR
Discussion:
FEC Convergence is a change in an LDP Binding of a prefix and
label to a peer's LDP Identifier. This change can be an update or
recovery due to a FEC Convergence Event. FEC Convergence is an
LSR action made prior to FEC Forwarding Table Convergence. FEC
Convergence is not an externally observable Black-Box measurement.
Measurement Units:
N/A
Issues:
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Where is LDP Identifier defined? Where is LDP Binding defined?
See Also:
LDP Binding Table
FEC Convergence Event
FEC Forwarding Table Convergence
3.16. FEC Convergence at Midpoint LSR
Definition:
Recovery from a FEC Convergence Event that causes the LDP Binding
Table to change and re-stabilize at a Midpoint LSR
Discussion:
FEC Convergence is a change in an LDP Binding of a prefix and
label to a peer's LDP Identifier. This change can be an update or
recovery due to a FEC Convergence Event. FEC Convergence is an
LSR action made prior to FEC Forwarding Table Convergence. FEC
Convergence is not an externally observable Black-Box measurement.
Measurement Units:
N/A
Issues:
Where is LDP Identifier defined? Where is LDP Binding defined?
See Also:
LDP Binding Table
FEC Convergence Event
FEC Forwarding Table Convergence
3.17. LDP Advertisement Type
Definition:
The type of LDP advertisement in operation. Downstream On Demand
vs Downstream Unsolicited.
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Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
None
3.18. Label Merging LSR
Definition:
A LSR which is capable of sending multiple packets out of the same
outgoing interface with the same label even though it receives
these packets from different incoming interfaces and may also
receive them with the same lane
Discussion:
With label merging the LSR need to send a single label per FEC and
also on the receiving end the number of incoming labels per FEC is
never larger than the number of label distribution adjacencies
Measurement Units:
N/A
Issues:
There maybe be scenarios where a Merging LSR is capable of merging
only a subset of incoming labels into a single outgoing label
See Also:
Non-Merging LSR and [RFC 3031]
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3.19. Non-merging LSR
Definition:
A LSR which forwards packets with multiple outgoing labels when it
receives packets from the same FEC with different incoming labels
Discussion:
Without label merging the number of outgoing labels per FEC could
be as large as the number of nodes in the network
Measurement Units:
N/A
Issues:
None
See Also:
Label Merging LSR and [RFC 3031]
3.20. LDPv6
Definition:
This term implies forwarding of IPv6 packets as detailed in [RFC
5036]
Discussion:
None
Measurement Units:
N/A
Issues:
The current specification [RFC 5036] has certain gaps as detailed
in [LDPv6]. Once its standardized we will extend the scope to
cover those details.
See Also:
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None
4. Factors impacting Convergence
4.1. Interaction with Other Protocols
LDP convergence must include the affect of interaction with IGPs.
All test reports must include the IGPs provisioned in the test and
their associated parameters
4.2. Timers
LDP convergence is impacted by the Hold and Keepalive Timers. Test
reports must include all the relevant timer values
4.3. TCP Parameters
As LDP uses TCP for sessions, all relevant TCP session parameters
must be reported
5. Security Considerations
Benchmarking activities as described in this memo are limited to
technology characterization using controlled stimuli in a laboratory
environment, with dedicated address space and the constraints
specified in the sections above.
The benchmarking network topology will be an independent test setup
and MUST NOT be connected to devices that may forward the test
traffic into a production network, or misroute traffic to the test
management network.
Further, benchmarking is performed on a "black-box" basis, relying
solely on measurements observable external to the DUT/SUT.
Special capabilities SHOULD NOT exist in the DUT/SUT specifically for
benchmarking purposes. Any implications for network security arising
from the DUT/SUT SHOULD be identical in the lab and in production
networks.
6. Acknowledgements
We thank Al Morton for providing valuable comments to this document.
We also thank Scott Poretsky for his contributions to the initial
version of this document.
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7. References
7.1. Normative References
[I-D.ietf-mpls-ldp-ipv6]
Asati, R., Manral, V., Papneja, R., and C. Pignataro,
"Updates to LDP for IPv6", draft-ietf-mpls-ldp-ipv6-08
(work in progress), February 2013.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005.
[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP
Specification", RFC 5036, October 2007.
[RFC6412] Poretsky, S., Imhoff, B., and K. Michielsen, "Terminology
for Benchmarking Link-State IGP Data-Plane Route
Convergence", RFC 6412, November 2011.
[RFC6413] Poretsky, S., Imhoff, B., and K. Michielsen, "Benchmarking
Methodology for Link-State IGP Data-Plane Route
Convergence", RFC 6413, November 2011.
7.2. Informative References
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
January 2007.
Authors' Addresses
Bhavani Parise
Cisco Systems
Email: bhavani@cisco.com
Rajiv Papneja
Huawei Technologies
Email: rajiv.papneja@huawei.com
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