Netmanias 기술문서: IEEE 802.1Qay PBT(PBB-TE)표준분석

IEEE 802.1Qay PBT(PBB-TE)표준분석
2007년12월15일
NMC Consulting Group(tech@netmanias.com)

2
PBT Basic Concepts
.Divide the B-VID space between PBBN B-VLANs and PBT
.PBBN MUST operate in IVL mode
.Turn off learning and broadcasting on all PBT B-VIDs
.On PBT B-VIDs replace flooding of unknown frames with discarding
.On PBT B-VIDs replace multicasting/broadcasting of frames with discarding
.Use a provisioning/management system to configure the bridge forwarding tables for PBT B-VIDs
.These are accessed through the bridge MIB
.Each PBT circuit is composed of a working and a protection path
.The working and the protection paths use different B-VIDs to access the same backbone MAC address (thus, PBBN MUST operate in IVL mode)
.Manage co-routed bundles of PBT backbone circuits using 802.1ag
.Requires unicast CC messages not currently implemented
.Management must operate on both the working and protected paths

3
PBT’s Main Features
BCB
BCB
BCB
BEB_B
BEB_A
Divide B-VID space & Turn off learning/flooding/multicast/broadcast on PBT B-VIDs
1
Use a provisioning/management system to configure the bridge forwarding tables for PBT B-VIDs
2
a3
B-VID Values
(Examples)
PBB or PBT?
STP
Learning
Flooding Unknown
Broadcast
Multicast

1 ~ 1000
PBB
Enable
Enable
Enable
Enable
Enable

1001 ~ 2500
PBT
Disable
Disable
Discard
Discard
Discard

2501 ~ 3000
PBB
Enable
Enable
Enable
Enable
Enable

3001 ~ 4094
PBT
Disable
Disable
Discard
Discard
Discard

MAC A
MAC B
1
2
2
1
3
1
2
1
2
1
2
3
1
2
1107378_L1
Provisioning System
B-DA=B,
B-VID=2001,
.
B-DA=B,B-VID=2001,.
BCB(=PB)
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-VLAN2001
B-VLAN2002
BCB
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
1
2
2
1
3
1
2
1
2
1
2
3
1
2
1107378_L1
Provisioning System
B-DA=A,B-VID=2001,.
B-DA=A,
B-VID=2001,
.
BCB(=PB)
B-DA=A,
B-VID=2001,
.
B-DA=A,
B-VID=2002,
.
B-VLAN2001
B-VLAN2002
B-DA=A,
B-VID=2002,
.
B-DA=A,
B-VID=2001,
.
B-DA=A,
B-VID=2002,
.
B-DA=A,
B-VID=2002,
.
Working ESP
Protection ESP
Working ESP
Protection ESP
Each PBT circuit is composed of a working and a protection path

4
PBT’s Main Features
Manage co-routed bundles of PBT backbone circuits using 802.1ag
BCB
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
BCB
B-VLAN2001
B-VLAN2002
Working Trunk
Protection Trunk
3
Unicast CC to A
Unicast CC to A
traffic
CC from B
CC from B
BCB
BCB
BCB
BEB_B
BEB_A
MAC B
BCB
B-VLAN2001
B-VLAN2002
Working Trunk
Protection Trunk
Unicast CC to A
Unicast CC to A
traffic
CC Lifetime Exceeded
CC from B
MAC A
1:1 Protection Switching
.CC_Lifetime = 3.5 X CC_Tx_Interval
.Continuity Check (CC) Message 보내는주기가10ms인경우, 35ms만에Fault Detect 가능함
.BEB 내에서Protection Switching 처리하는시간이15ms 미만이면, “Transfer Time 50ms 이하”(SONET 수준)를만족할수있음
802.1ag CC messages are sent in-band in the reverse direction of each ESP

5
Terms of PBT
.Ethernet Switched Path (ESP)
.A provisioned path between two VIPswhich extends over a PBBN (in 802.1Qay D0.0, May 2007)
.A provisioned unidirectionalpath across the PBBN between two CBPs(Nokia-Siemens, Sep 2007)
.PBT Trunk
.A pair of unidirectional ESPs between the same pair of CBPs, one on each direction
.Trunk Protection Group (TPG)
.A Working PBT Trunkis provisioned to transfer traffic in normal conditions
.A Protection PBT Trunkis provisioned to protect the corresponding working trunk
.Trunk Operational State = Up / Down
.Trunk Forwarding State = Active / Standby
.그Trunk가Traffic을Forwarding하는상태이면“Active Forwarding State에있다”고말함
.그렇지않으면“Standby Forwarding State”에있다고말함

6
I-Component
B-Component
PNP#1
I-SID=1010
I-SID-1011
PIP
CBP
Backbone Edge Bridge (BEB)
PNP#2
ESP, Trunk & TPG
S-VID=10
S-VID=11
I-Component
B-Component
PNP#1
I-SID=1010
I-SID-1011
VIP#1
VIP#2
PIP
CBP
Backbone Edge Bridge (BEB)
PNP#2
B-VID=2001
TPG
B-VID=2001
TPG
B-VID=2002
B-VID=2002
Working trunk
Protection trunk
BCB
S-VID=10
S-VID=11
VIP#1
VIP#2
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
B-DA=B,
B-VID=2001,
.
BCB(=PB)
B-DA=B,B-VID=2001,.
B-DA=B,
B-VID=2001,
.
B-VLAN2001
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
B-DA=A,
B-VID=2001,
.
B-DA=A,
B-VID=2001,
.
BCB(=PB)
B-DA=A,
B-VID=2001,
.
B-VLAN2001
B-DA=A,
B-VID=2001,
.
ESP .
ESP .
B-DA=B,
B-VID=2001,
.
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
BCB(=PB)
B-VLAN2001
Trunk

7
How to allocate B-VIDs to PBT Context
.Define a special MST-ID called PBT-ID(=0xFFE)
.MST-ID = 0xFFE identifies PBT (Not an MST instance)
.MST-ID 0xFFE는, “여기에속한B-VID는어느MST Instance에도속하지않으며, PBT 영역에속한다”는의미임
.“FID-to-MSTID Allocation Table” 상에, PBT-ID에해당하는FID를할당
.i.e. FID = 255 to MSTID=0xFFE
.“MST Configuration Table” 상에, PBT-ID에VID 할당
.PBT (MST-ID=0xFFE)에속한VLAN 내에서의Port state : Forwarding=on, Learning=off

8
1:1 Ethernet Protection Switching
.PBT references ITU-T G.8031 “Ethernet Protection Switching”
.1:1 Unidirectional/Bidirectional
.1+1 Unidirectional/Bidirectional
.Optional “extra traffic” on protection path in case of 1:1 protection
.Revertive / Non-revertive
.1-,2-,3-phase APS Protocols
.User-initiated, Automatic
.PBT standardization objectives
.1:1 Bi-directional protection
.Unicast CCM
.1-phase APS signaling
.No extra traffic on protection path (BT)
.Configurable Revertive/Non-revertive protection (BT)
.Lock-out-of-protection, Manual Switch command should be supported (BT)

9
1:1 Protection Architecture

10
1:1 Unidirectional vs. 1:1 Bidirectional Switch
1:1 Unidirectional Switch
1:1 Bidirectional Switch

11
APS Signaling

12
1-phase APS Protocol

13
2-phase APS Protocol

14
3-phase APS Protocol

15
Scalability Factors of PBT
Key Scalability Index
Description
제약요소인가?

I-SID space
224=~ 16M
No

Max. # of PBT Trunks
258(I-SID space의제곱)
(12bit VID + 48bit MAC Address .2bit)
No

Bandwidth of CCM
CCM at 10ms interval .6.4KBytes/s = 51.2kbps per Trunk
(64byte X 100times/s = 6.4KB/s)
No

CCM Packet Processing Performance of a BEB
For 1,000 trunks with 50ms protection, the total load is ~400,000 fps
(= 1,000 trunks X 100fps X bi-direction X dual-trunks)
Yes

Size of the database (memory) of the Provisioning system
“Provisioning System은Global PBT Network 내의모든PBT trunk를Provisioning해야함”(Nortel)
-1개의{B-DA, B-VID, Port}-tuple= 48 + 12 + 8 bits .9 Bytes
#NAME?
-1,000,000개trunk에대해12MB memory 소모
Yes/No*

Size of the MAC address table of each bridge
For a bridge through which 1,000 trunks pass, 2,000 entriesof {B-DA, B-VID, Port}-tupleare needed
No
Customer Address를배워야하는BEB들의경우, PBT trunk 외부의모든단말의주소를배워야함
Yes

* 802.1Qay Working Group 에제출된Nortel의문서상으로는Global PBT 전송망이Deploy될경우Provisioning System의DB size가실질적인PBT Scalability를결정할것으로언급하고있으나, 유무선backhaul solution으로서PBT를사용할경우에는Global 망의규모보다는작아지기때문에큰제약사항이되지않을것임

16
PBT Tunnel Provisioning
.PBT는MPLS와달리Tunnel을setup하기위한Signaling Protocol이필요없음
.중앙집중형PBT Provisioning System을통해Topology Map 관리, Static PBT ESP Setup 기능이수행되어야함
.Static ESP Setup = Static MAC Address Setup
.Static MAC Address 설정을SNMP Set 기능으로수행할수있으므로, PBT Provisioning System과NMS/EMS tool이통합될수있음
BCB
BCB
BCB
BEB_B
BEB_A
Use a provisioning/management system to configure the bridge forwarding tables for PBT B-VIDs
MAC A
MAC B
1
2
2
1
3
1
2
1
2
1
2
3
1
2
1107378_L1
Provisioning System
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2001,
.
BCB(=PB)
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,B-VID=2002,.
B-DA=B,B-VID=2002,.
B-VLAN2001
B-VLAN2002
BCB
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
1
2
2
1
3
1
2
1
2
1
2
3
1
2
1107378_L1
Provisioning System
B-DA=A,
B-VID=2001,
.
B-DA=A,
B-VID=2001,
.
BCB(=PB)
B-DA=A,
B-VID=2001,
.
B-DA=A,
B-VID=2002,
.
B-VLAN2001
B-VLAN2002
B-DA=A,B-VID=2002,.
B-DA=A,B-VID=2001,.
B-DA=A,
B-VID=2002,
.
B-DA=A,
B-VID=2002,
.
Working ESP
Protection ESP
Working ESP
Protection ESP
Each PBT circuit is composed of a working and a protection path

17
PBT Backhaul망을위한OMC의주요기능
기능
설명

PBT Provisioning
Topology Map 관리및ESP Provisioning
.MIB을읽어PBT NE간의connectivity 파악및Graphical Topology Map 그리기기능
.GUI를이용한Ethernet Switched Path (=ESP) Manual Provisioning 기능
.SPF, C-SPF Algorithm을이용한ESP 자동계산및Provisioning 기능

NMS/EMS
Network Management
.PB, PBB 장비의주요기능에대한SNMP Get/Set이가능하여야함
.특히, 다음기능들을SNMP로설정할수있어야함
.PB/PBB Mode VLAN과PBT Mode VLAN 설정
.Static MAC Address 설정
.802.1ag CC interval 및CC Lifetime 설정
Syslog 및Alarm (Trap) Logger
.Syslog 및SNMP Trap의형태로다음의상태정보를수집, 관리하여야함
.802.1ag Continuity Check의Failure
.Trunk 상태정보(Working/Protection/Active/Standby)
.기타, Link Up/Down, Board Fail 등표준적인Alarm 정보

BCB
BCB
BCB
BEB_B
BEB_A
MAC A
MAC B
1
2
2
1
3
1
2
1
2
1
2
3
1
2
1107378_L1
NMS/EMS,
Provisioning System
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2001,
.
BCB(=PB)
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2001,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-DA=B,
B-VID=2002,
.
B-VLAN2001
B-VLAN2002
Working ESP
Protection ESP
OMC
1107378_L1

18
References on PBT
.802-1-ay-d0-0.pdf (IEEE 802.1Qay Working Group, May 22, 2007)
.new-bottorff-pbt-par-present-1006-01.pdf (July 2006) .Nortel
.ay-alon-protection-switching-0907-v01.pdf (Sep. 2007) .Nokia-Siemens
.ay-mcguire-linear-121-protsw-0709-v1.pdf (Sep. 2007) .BT
.ay-martin-protection-0707-v01.pdf (July 2007) .Nortel

19
End of Document