Segment Routing -もうLDP/RSVPはいらない-

Segment Routing
-もうLDP/RSVPはいらない-
Shishio Tsuchiya
sht[email protected]
©
© 2010
2010 Cisco
Cisco and/or
and/or its
its affiliates.
affiliates. All
All rights
rights reserved.
reserved.
Cisco Confidential
1
Agenda
•  Segment Routing Overview
•  Complex of legacy MPLS
•  Segment Routing use case
•  IETF Status
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2
サービス・プロバイダーの憂鬱
•  トラフィック・パターンの多様化
•  マルチサービス/共通基盤
•  レベニューモデルの変化
•  パス・スケーラビリティ
•  経路爆発
•  管理コスト
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3
MPLSDN
管理コストと複雑さを増加させずに、より速くサービスを達成する方法とは?
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4
Segment Routing
64
draft-previdi-filsfils-isis-segment-routing
67
68
70
•  ネットワークをSegmentで表現する
71
65
69
66
•  SegmentにはNodeとAdjacency2つの要素がある
2adj
4adj
•  LDP/RSVPを使わず、直接IGPによりこれらのIDをアドバタイズする
•  ネットワークからLDP/RSVPのステートを排除する事が出来る
•  現在はdraft-filsfils-rtgwg-segment-routingにてアーキテクチャーを定義
Node Segment
64
67
Adjacency Segment
68
70
64
71
65
69
66
106
105
70
106
67
65
68
102
101
71
69
66
105
105
102
102
102
71
71
71
71
101
101
101
101
data
data
data
data
data
data
data
data
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5
Segment Routing
Combination NodeID+AdjID draft-previdi-filsfils-isis-segment-routing
71に行くには67,68
経由で到達
67
105
71
data
105
64
data
71
67
68
data
105
70
71
65
66 71
data
69
data
•  Node IDとAdjacency IDの組み合わせも可能 © 2010 Cisco and/or its affiliates. All rights reserved.
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Agenda
•  Segment Routing Overview
•  Complex of legacy MPLS
•  Segment Routing use case
•  IETF Status
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7
MPLS OAM Requirement
Control Plane!
IP Routing Protocols
OSPF/ISIS/BGP/EIGRP/RIP
IP Routing Table"
Label Information Base
(LIB)"
Data Plane!
CEF"
Switching"
MPLS Label "
Control Protocol"
TDP/LDP/RSVP/CR-LDP/BGP
Forwarding Information
Base (FIB)"
Label Forwarding
Information Base (LFIB)"
•  コントロールプレーンとデータプレーンを分離
•  データプレーンを確認するための新しいOAMツール(RFC4379)が必要に
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MPLS LDP IGP Synchronization(RFC5443)
LFIB
LFIB
LFIB
LFIB
FIB
FIB
FIB
FIB
LFIB
LFIB
FIB
FIB
65535
LFIB
LFIB
LFIB
LFIB
FIB
FIB
FIB
FIB
•  2つ以上のコントロールプレーン/データプレーンを使う為に
相互での矛盾が起こりうる
•  LDP Stateの監視を行いMax Metricでコントロールをする
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Discovery of MPLS LSR TE Mesh Membership
(RFC4972)
Blue is Voice,12 tunnels
Red is Video,12 tunnels
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
mesh-group-number 1
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Tail-end IPv4 address 1
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length |
Tail-end name 1
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
//
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
mesh-group-number n
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Tail-end IPv4 address n
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Name length |
Tail-end name n
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
•  RSVPのパスセットアップに必要なTEDBの為にOSPF/ISISを拡
張(RFC3630/RFC5305)
•  ノードがどのMesh Groupに入るかの伝播も拡張し、設定負荷な
どを軽減
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まとめ
•  コントロールプレーンとデータプレーンが大きく離れて
いるので、追加でOAMが必要に
•  コントロールプレーンが複数あるので、監視する仕組み
が必要に
•  多くの設定を要する為に、設定情報を分散させる仕組
みが必要に
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11
Agenda
•  Segment Routing Overview
•  Complex of legacy MPLS
•  Segment Routing use case
•  IETF Status
© 2010 Cisco and/or its affiliates. All rights reserved.
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12
Applicability
Simplicity/Scalable TE
PE
PE
•  Simplicity
VPNサービスの為にはPEのNode IDを知ってるのみで良い
IGP/LDPのSyncなどを気にする必要が無くなる
一つのプロトコルのみの運用
•  Scalable TE
RSVP TEでフルメッシュの運用をすると、N-1のHead/TailおよびN(N-1)/2 midpoint LSP
の管理が必要
SRではStateを管理する必要が無い。State in the packet
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Applicability
Simple Disjointness/CoS Based TE
•  Simple Disjointness
品質の厳しい顧客にはプライマリ/セカンダリが互いに分離したパスが必要になる。
SRであればNode IDをStackする事でコントロールが可能
•  CoS Based TE
データは回線コストの安いUS経由/VoIPは低遅延のロシア経由など
品質に応じたトラフィックエンジニアリングも実施可能
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Applicability
Segment Routing in Software Defined Networks
(SR-SDN)
FULL
68
9,7
6
,
8
{6
0}
70
69
帯域の問題は
無し
•  ネットワークがシンプルなので、パスセットアップも非常
に簡単になる
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15
Agenda
•  Segment Routing Overview
•  Complex of legacy MPLS
•  Segment Routing use case
•  IETF Status
© 2010 Cisco and/or its affiliates. All rights reserved.
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16
Segment Routing IETF Status
•  IETF 87 - Berlin, Germany
Stacked Tunnels for Source Routing (STATUS) BOF
http://www.ietf.org/proceedings/87/status.html
•  IETF 88 - Vancouver, BC, Canada
"Source Packet Routing in Networking" (spring) WG
https://datatracker.ietf.org/doc/charter-ietf-spring/
Milestones:
ü 
ü 
ü 
ü 
High Level Architecture
MPLS Architecture/IPv6 Architecture
Use case
OAM/Inter-work/interop report etc..
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IETF Activity http://tools.ietf.org/wg/spring/
•  SRアークテクチャー draft-filsfils-rtgwg-segment-routing
•  Use case
draft-filsfils-rtgwg-segment-routing-use-cases
•  SRの為のISIS拡張
draft-previdi-isis-segment-routing-extensions
•  SRの為のOSPF拡張
draft-psenak-ospf-segment-routing-extensions
draft-psenak-ospf-segment-routing-ospfv3-extension
•  SR with MPLS
draft-filsfils-spring-segment-routing-mpls
draft-filsfils-spring-segment-routing-ldp-interop
draft-kumar-mpls-spring-lsp-ping
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OSPF Extended Prefix TLV
draft-psenak-ospf-segment-routing-extensions
• 
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Type(1)
|
Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Type
| Prefix Length |
AF(0)
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Address Prefix (variable)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Sub-TLVs (variable)
|
+-+
|
|
OSPFルートタイプ:
0 - unspecified
1 - intra-area
3 - inter-area
5 - external
7 - NSSA external
Opaque TLVを用いてSIDを伝播
AF:0 IPv4 unicast
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Prefix SID Sub-TLVdraft-psenak-ospf-segment-routing-extensions
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Type(2)
|
Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Flags
|
MT-ID
|
Algorithm |
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Index
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|N|P|M|
|
+-+-+-+-+-+-+-+-+
•  N-Flag: Node-SID flag.NodeSIDかどうかを示す。
•  P-Flag: no-PHP flag.セットしてあればPHPをしてはならない
•  M-Flag: Mapping Server Flag.セットしてあればMapping Serverによりア
ドバタイズされた
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SID/Label Binding sub-TLV
draft-psenak-ospf-segment-routing-extensions
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Type
|
Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Flags
|
MT-ID
| Weight
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Sub-TLVs (variable)
|
+-+
|
|
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
M-Flag: IP FRR/MPLS FRRによる保護されている
|M|
|
Weightはロードバランスに使用される
+-+-+-+-+-+-+-+-+
•  Prefixへのパスを示す
•  SubTLVにはERO Metric sub-TLV/IPv4 ERO sub-TLV
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ERO Metric sub-TLV
draft-psenak-ospf-segment-routing-extensions
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Type(8)
|
Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Metric (4 octets)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|
•  Metric Source/Destinationのコスト比較の為に使用する
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IPv4 ERO subTLV
draft-psenak-ospf-segment-routing-extensions
0
1
2
3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Type(4)
|
Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Flags
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
IPv4 Address (4 octets)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
L-bit:ビットが立っているとloose/無ければstrict
|L|
|
+-+-+-+-+-+-+-+-+
•  Backup ERO/unnumbered ERO subTLVなどがある
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•  Images available for ASR9000, CRS and XR12000
•  Prototype supports
MPLS data plane
Node segment id
IS-IS
•  Implementation based on 4.3.1 code
•  Available for customer lab use
•  CLI not final
© 2011 Cisco and/or its affiliates. All rights reserved. –
[email protected]
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Nodal-id configuration
router isis abc
net 47.0000.0000.0000.1111.00
address-family ipv4 unicast
1
2
3
4
metric-style wide
!
address-family ipv6 unicast
!
interface Loopback0
passive
address-family ipv4 unicast
nodal-sid sid-value 16001
!
address-family ipv6 unicast
nodal-sid sid-value 16901
!
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show isis database
RP/0/RSP0/CPU0:ASR9k-1#sh isis database verbose
IS-IS abc (Level-1) Link State Database
LSPID
LSP Seq Num
ASR9k-1.00-00
* 0x00000057
LSP Checksum
LSP Holdtime
0x9e4e
675
ATT/P/OL
1
2
3
4
0/0/0
Area Address: 47.0000
NLPID:
0xcc
NLPID:
0x8e
MT:
Standard (IPv4 Unicast)
MT:
IPv6 Unicast
Hostname:
ASR9k-1
IP Address:
10.1.255.1
0/0/0
IPv6 Address: 2001:db8:ffff::1
Metric: 10
IS-Extended ASR9k-2.00
Metric: 10
IP-Extended 10.1.13.0/24
Metric: 0
IP-Extended 10.1.255.1/32
Nodal-SID: 16001 PHP-off:0 Ext:0
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show mpls fowarding
RP/0/RSP0/CPU0:ASR9k-1#sh mpls for
Local
Outgoing
Prefix
Outgoing
Label
Label
or ID
Interface
Next Hop
Bytes
Switched
1
2
3
4
------ ----------- ------------------ ------------ --------------- -----------16001 Aggregate
default: Per-VRF Aggr[V]
\
default
0
0
16002
Pop
No ID
Te0/0/0/0
10.1.12.2
752
16003
Pop
No ID
Te0/0/0/1
10.1.13.3
0
16004
16004
No ID
Te0/0/0/0
10.1.12.2
0
16004
No ID
Te0/0/0/1
10.1.13.3
0
16902  Pop
No ID
Te0/0/0/0
fe80::6e9c:edff:fe30:de0
\ 1112
16903  Pop
No ID
Te0/0/0/1
fe80::4255:39ff:fe7f:fbe9
\ 0
16904  16904
No ID
Te0/0/0/0
fe80::6e9c:edff:fe30:de0
16904
No ID
Te0/0/0/1
fe80::4255:39ff:fe7f:fbe9
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\ 0
\ 0
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show cef x.x.x.x
RP/0/RSP0/CPU0:ASR9k-1#sh cef 10.1.255.4
Wed Jun 26 15:34:16.877 UTC
1
2
3
4
10.1.255.4/32, version 10515396, internal 0x4004001 (ptr 0x7630ff20) [1], 0x0 (0x71202dd8), 0x450 (0x7665c050)
Updated Jun 26 15:26:10.750
remote adjacency to TenGigE0/0/0/0
Prefix Len 32, traffic index 0, precedence n/a, priority 1
via 10.1.12.2, TenGigE0/0/0/0, 8 dependencies, weight 0, class 0 [flags 0x0]
path-idx 0 [0x72372224 0x0]
next hop 10.1.12.2
remote adjacency
local label 16004
labels imposed {16004}
via 10.1.13.3, TenGigE0/0/0/1, 9 dependencies, weight 0, class 0 [flags 0x0]
path-idx 1 [0x723721c8 0x0]
next hop 10.1.13.3
remote adjacency
local label 16004
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labels imposed {16004}
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まとめ
•  Segment RoutingではOSPF/ISISにて直接データプレー
ン情報をアドバタイズする事で複雑さを回避/ステータ
スの管理を軽減する
•  シンプルにする事により、アプリケーションとの連動をし
やすいコアネットワークを構築可能に
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Thank you.