draft-ietf-rtgwg-mofrr-06.txt   draft-ietf-rtgwg-mofrr-07.txt 
Network Working Group A. Karan Network Working Group A. Karan
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Informational IJ. Wijnands, Ed. Intended status: Informational IJ. Wijnands, Ed.
Expires: August 8, 2015 Cisco Systems, Inc. Expires: November 13, 2015 Cisco Systems, Inc.
B. Decraene B. Decraene
Orange Orange
February 4, 2015 May 12, 2015
Multicast only Fast Re-Route Multicast only Fast Re-Route
draft-ietf-rtgwg-mofrr-06 draft-ietf-rtgwg-mofrr-07
Abstract Abstract
As IPTV deployments grow in number and size, service providers are As IPTV deployments grow in number and size, service providers are
looking for solutions that minimize the service disruption due to looking for solutions that minimize the service disruption due to
faults in the IP network carrying the packets for these services. faults in the IP network carrying the packets for these services.
This document describes a mechanism for minimizing packet loss in a This document describes a mechanism for minimizing packet loss in a
network when node or link failures occur. Multicast only Fast Re- network when node or link failures occur. Multicast only Fast Re-
Route (MoFRR) works by making simple enhancements to multicast Route (MoFRR) works by making simple enhancements to multicast
routing protocols such as PIM and mLDP. routing protocols such as PIM and mLDP.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 8, 2015. This Internet-Draft will expire on November 13, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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2. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 4 2. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 4
3. Determination of the secondary UMH . . . . . . . . . . . . . 4 3. Determination of the secondary UMH . . . . . . . . . . . . . 4
3.1. ECMP-mode MoFRR . . . . . . . . . . . . . . . . . . . . . 4 3.1. ECMP-mode MoFRR . . . . . . . . . . . . . . . . . . . . . 4
3.2. Non-ECMP-mode MoFRR . . . . . . . . . . . . . . . . . . . 5 3.2. Non-ECMP-mode MoFRR . . . . . . . . . . . . . . . . . . . 5
4. Upstream Multicast Hop Selection . . . . . . . . . . . . . . 5 4. Upstream Multicast Hop Selection . . . . . . . . . . . . . . 5
4.1. PIM . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. PIM . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. mLDP . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.2. mLDP . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Detecting Failures . . . . . . . . . . . . . . . . . . . . . 6 5. Detecting Failures . . . . . . . . . . . . . . . . . . . . . 6
6. MoFRR applicability . . . . . . . . . . . . . . . . . . . . . 7 6. MoFRR applicability . . . . . . . . . . . . . . . . . . . . . 7
6.1. Dual-Plane Topology . . . . . . . . . . . . . . . . . . . 7 6.1. Dual-Plane Topology . . . . . . . . . . . . . . . . . . . 7
6.2. Capacity Planning for MoFRR . . . . . . . . . . . . . . . 10 6.2. Other Topologies . . . . . . . . . . . . . . . . . . . . 10
6.3. PE nodes . . . . . . . . . . . . . . . . . . . . . . . . 11 6.3. Capacity Planning for MoFRR . . . . . . . . . . . . . . . 11
6.4. Other Applications . . . . . . . . . . . . . . . . . . . 11 6.4. PE nodes . . . . . . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 6.5. Other Applications . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
10. Contributor Addresses . . . . . . . . . . . . . . . . . . . . 12 10. Contributor Addresses . . . . . . . . . . . . . . . . . . . . 12
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . 13 11.1. Normative References . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . 13 11.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
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Source Source
/ \ / \
Plane1 Plane2 Plane1 Plane2
| | | |
A1 A2 A1 A2
| | | |
PE1----PE2 PE1----PE2
FIG3. PEs are connected in pairs to Dual-Plane Backbone FIG3. PEs are connected in pairs to Dual-Plane Backbone
6.2. Capacity Planning for MoFRR 6.2. Other Topologies
As mentioned in section Section 6.1, MoFRR works best in dual-plane
topologies. If MoFRR is applied to none dual-plane networks, its
possible that the secondary path is effected by the same failure that
effected the primary path. In that case, there is no guarentee that
the backup path will provide an un-interupted traffic flow of packets
without loss or duplication.
6.3. Capacity Planning for MoFRR
The previous section has described two very frequent designs (Fig 2 The previous section has described two very frequent designs (Fig 2
and Fig 3) which provide maximum MoFRR benefits. and Fig 3) which provide maximum MoFRR benefits.
Designers with topologies different than Fig2 and 3 can still benefit Designers with topologies different than Fig2 and 3 can still benefit
from MoFRR thanks to the use of capacity planning tools. from MoFRR thanks to the use of capacity planning tools.
Such tools are able to simulate the ability of each PE to build two Such tools are able to simulate the ability of each PE to build two
disjoint branches of the same tree. This for hundreds of PEs and disjoint branches of the same tree. This for hundreds of PEs and
hundreds of sources. hundreds of sources.
This allows to assess the MoFRR protection coverage of a given This allows to assess the MoFRR protection coverage of a given
network, for a set of sources. network, for a set of sources.
If the protection coverage is deemed insufficient, the designer can If the protection coverage is deemed insufficient, the designer can
use such tool to optimize the topology (add links, change IGP use such tool to optimize the topology (add links, change IGP
metrics). metrics).
6.3. PE nodes 6.4. PE nodes
Many Service Providers devise their topology such that PEs have Many Service Providers devise their topology such that PEs have
disjoint paths to the multicast sources. MoFRR leverages the disjoint paths to the multicast sources. MoFRR leverages the
existence of these disjoint paths without any PIM or mLDP protocol existence of these disjoint paths without any PIM or mLDP protocol
modification. Interoperability testing is thus not required. In modification. Interoperability testing is thus not required. In
such topologies, MoFRR only needs to be deployed on the PE devices. such topologies, MoFRR only needs to be deployed on the PE devices.
Each PE device can be enabled one by one. Each PE device can be enabled one by one.
6.4. Other Applications 6.5. Other Applications
While all the examples in this document show the MoFRR applicability While all the examples in this document show the MoFRR applicability
on PE devices, it is clear that MoFRR could be enabled on aggregation on PE devices, it is clear that MoFRR could be enabled on aggregation
or core routers. or core routers.
MoFRR can be popular in Data Center network configurations. With the MoFRR can be popular in Data Center network configurations. With the
advent of lower cost ethernet and increasing port density in routers, advent of lower cost ethernet and increasing port density in routers,
there is more meshed connectivity than ever before. When using a there is more meshed connectivity than ever before. When using a
3-level access, distribution, and core layers in a Data Center, there 3-level access, distribution, and core layers in a Data Center, there
is a lot of inexpensive bandwidth connecting the layers. This will is a lot of inexpensive bandwidth connecting the layers. This will
lend itself to more opportunities for ECMP paths at multiple layers. lend itself to more opportunities for ECMP paths at multiple layers.
This allows for multiple layers of redundancy protecting link and This allows for multiple layers of redundancy protecting link and
node failure at each layer with minimal redundancy cost. node failure at each layer with minimal redundancy cost.
Redundancy costs are reduced because only one packet is forwarded at Redundancy costs are reduced because only one packet is forwarded at
every link along the primary and secondary data paths so there is no every link along the primary and secondary data paths so there is no
duplication of data on any link thereby providing make-before-break duplication of data on any link thereby providing make-before-break
protection at a very small cost. protection at a very small cost.
A MoFRR router only accepts packets from the primary path and
discards packets from the secondary path. For that reason,
management applications (like ping and mtrace) will not work when
verifying the secondary path.
The MoFRR principle may be applied to MVPNs. The MoFRR principle may be applied to MVPNs.
7. IANA Considerations 7. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
8. Security Considerations 8. Security Considerations
There are no security considerations for this design other than what There are no security considerations for this design other than what
is already in the main PIM specification [RFC4601] and mLDP is already in the main PIM specification [RFC4601] and mLDP
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