Download B-TAG - Cloud.cz

Rozšiřitelnost a
vysoká dostupnost
v L2 sítích
Techtorial
Jiří Tesař
Systems Engineer
CCIE #14558
[email protected]
Sponsor
Logo
CIscoEXPO
Sponsor
Sponsor
Sponsor
Logo
Logo
Logo
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
1
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
2
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
802.1ah Terminologies
  BEB: Backbone Edge Bridge – encapsulates customer frames for
transmission across backbone.
  B-BEB: B type BEB – contains a B-component, supports bridging in the
provider backbone based on B-MAC and B-TAG info.
  I-BEB: I type BEB – contains an I-component for bridging in the customer
space, including customer MAC, service VLAN IDs.
  B-TAG: Backbone VLAN Tag – an S-TAG used in conjunction with
backbone MAC addresses.
  I-TAG: Service Instance Tag - encapsulates customer addresses and
contains the Service Instance identifier (I-SID).
  I-SID: Service Instance identifier - A field of the Service Instance tag
which identifies the service instance of the frame.
  S-TAG: A field defined in the 802.1ad Q-in-Q encapsulation which
identifies the Service VLAN (S-VLAN).
3
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
802.1ah Terminologies and Interconnections
CE
MPLS
Core
PE
I
Peer
802.1ah
PBBN
B
BEB
I
IB
BEB
B
I BEB
B
I
B
I
PE/
BEB
MPLS
Core
P
I
BEB
I type
Backbone
Edge Bridge
CiscoEXPO
C
S
I
C-Tagged
Interface
S-Tagged
Interface
I-Tagged
Interface
B
BEB
B type
Backbone
Edge Bridge
S
CE
C
CE
Q
C
CE
Q
C
B
S
PEB
C
C
Q
C
B-Tagged
Interface
MPLS
Interface
PE/
BEB
PB
PEB
Q
CE
IB type
Backbone
Edge Bridge
MPLS PE and
Backbone
Edge Bridge
Provider
Bridge
(S Bridge)
Provider
Edge Bridge
(C + S) Bridge
802.1Q
C Bridge
Customer
Equipment
Cisco Public
CE
M
IB
BEB
© 2010 Cisco Systems, Inc. All rights reserved.
CE
PB
802.1Q
I
BEB
M
Legend:
S
S
I
BEB
B
B
I
S
B
BEB
CE
PEB
PB
B
B
C
S
S
S
BCB
(PB)
B
802.1ad / Q-in-Q
PBN
B
B
B
BEB
Hierarchical B
802.1ah
BEB
PBBN
C
802.1ah
PBBN
4
IEEE 802.1ah – Provider Backbone Bridges
(PBB)
I-TAG: Contains 24 Bits to
Identify a Service Instance
B-DA
B-SA
Second MAC-Header
B-TAG TPDNRI
C-DA
C-SA
C-TAG
B-TAG: Equals S-TAG
L2 PDU
FCS
P802.1ah (Provider Backbone Bridges)
Encapsulation Example
  Service Scalability
Define a new “Service Instance Identifier”—24 Bits wide
(taking the place of the former “VLAN”): I-SID
  Domain Isolation, MAC-Address Scalability
Encapsulate Customer MAC-frames at the edge of the network into a “Provider MACFrame”: New MAC-Header with B-TAG
  “Backward Compatibility” to 802.1ad
Packet header of Provider Backbone Bridges (PBB, P802.1ah)
and Provider Bridges (PB, P802.1ad) look the same
802.1ah assumes existing L2 control plane mechanisms such as spanning tree;
however these are not required
5
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
802.1ah I-TAG
B-DA
I-PCP
C-SA
C-TAG
4–6
Res2
Ether-Type
(0x88-e7)
Bits
C-DA
3
Res1
1–2
B-TAG TPDNRI
I-DEI
NCA
Octets
B-SA
L2 PDU
7–12
I-SID
FCS
13–18
C-SA
C-DA
8 7 6 5 4 3 2 1
802.1ah Frame Format Settled
  Priority Code Point (I-PCP)
  Drop Eligible Indicator (I-DEI)
  No Customer Addresses (NCA)
  Reserved 1 (Res1)
  Reserved 2 (Res2)
  Backbone Service Instance Identifier (I-SID)
6
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Ethernet Encapsulation Evolution
C-DA: Customer dest addr
C-SA: Customer src addr
C-TAG: Customer tag
S-TAG: Service tag
B-DA: Backbone dest addr
S-SA: Backbone src addr
I-TAG: Service instance tag
VID: VLAN identifier (part of C-/S-/
B-TAG)
I-SID: Backbone service instance
identifier (part of I-TAG)
Service
Instances
(I-SID)
224=16,777,216
B-DA
Service
Instances
(VID)
12
2 =4,096
B-TAG
C-DA
C-DA
C-DA
C-SA
C-SA
C-DA
C-SA
S-TAG
S-TAG
C-SA
C-TAG
C-TAG
C-TAG
Payload
Payload
Payload
Payload
FCS
FCS
FCS
FCS
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
B-SA
I-SID
PB: Provider Bridges
PBB: Provider backbone bridges
I-TAG
Service
Instances
(VID)
212=4,096
802.1Q/ad
service
Instances (212)
802.1ah
service
Instances (224)
7
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
8
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
7600 – 802.1ah Line Card Support
ES+
ES+
UNI
NNI
Ingress
IB-BEB
ES+
or
Any
DFC
UNI
NNI
ES+
or
Any
DFC
BCB
Egress
IB-BEB
  802.1ah Imposition/Disposition is done on UNI facing ES+ cards
  NNI Facing Line card
1. 
2. 
CiscoEXPO
Any DFC card
Adds B-VID
© 2010 Cisco Systems, Inc. All rights reserved.
7600 802.1ah LC Requirements
Ingress LC
Egress LC
Native 802.1ah
ES+
Any DFC card
(Recommend ES+)
802.1ah + MPLS
ES+
ES+, ES20, SIP600, SIP400
(Recommend ES+)
Cisco Public
9
7600 VLAN Local Significance Support
Interface Types
ES+
ES20
SIP400
67xx
EVC Dot1q
Yes
Yes
Yes
N/A
EVC QinQ
Yes
Yes
Yes
N/A
Sub-interface Dot1q
Yes
No
Yes
No
Sub-interface QinQ
Yes
Yes
Yes
N/A
 
 
VLAN Local Significance does means
• 
VLAN is terminated in the NPU => VLAN lookup, rewrites, etc … are performed in
NPU
• 
Same VLAN tag can be used on multiple ports
• 
VLAN tag leaving the port is different to VLAN allocated in internal Database
VLAN Local Significance does NOT mean
• 
More than 4000 VLANs are supported for Layer 3 termination
10
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Flexible Forwarding Model
P2P XCONNECT
EVC to L3/VRF
C-BRIDGE
C
P2P X
C
ONNE
MPLS
L3
T
CON
VFI X
NECT
B-BRIDGE
EFPs
L2 B
R
L2 BRIDGED
L2
L2
IDG
E
D
EFPs
Local Connect
TRUNK
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
11
Flexible Ethernet Edge Example
Access port
ES
Local
connect
Service instance or
Ethernet Flow Point
CiscoEXPO
AS
core interface, L2
trunk or L3 MPLS
CS
service instance 1 ethernet
encapsulation dot1q 20 second-dot1q 10
rewrite ingress tag pop 1 sym
bridge-domain 10 c-mac
802.1ah (PBB
or .1ah over
VPLS
service instance 2 ethernet
encapsulation dot1q 11-100
rewrite ingress tag push dot1q 101
xconnect 1.1.1.1 1000 en mpls
E-LINE
(VPWS)
service instance 3 ethernet
encapsulation dot1q 101 second-dot1q 10
rewrite ingre tag translate 2-to-1 100
bridge-domain 200
Interface vlan 200
xconnect vfi myvpls
E-LAN (VPLS
or Local
bridging)
service instance 4 ethernet
encapsulation dot1q 102
rewrite ingress tag pop 1
bridge-domain 201
Interface vlan 201
ip address 2.2.2.2 255.255.255.0
ip vrf myvrf
L3 termination
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
12
IEEE 802.1ah Control Plane Model
IB-BEB
I-Component
B-Component
C-MAC Lookup Function
MAC Relay
B-MAC Lookup Function
MAC Relay
EFP
I-EFP
B-EFP
(Physical)
(Virtual)
(Virtual)
Switch
Port
(Physical)
CIP
PIP
CBP
B-MAC Tagging/
I-SID Insertion
B-VLAN Re-write/
I-SID Validation
PBP
Ingress EFP (802.1ah UNI)
MAC Tunnel
Egress switchport (NNI)
int gig1/1
ethernet mac-tunnel virtual abc.com
bridge-domain 100
int gig1/2
service instance 15 ethernet
encapsulation dot1q 9 second-dot1q 8
bridge-domain 10 c-mac
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
service instance 31 ethernet
encapsulation i-sid 10000
bridge-domain 10 c-mac
switchport
switchport mode trunk
switchport allowed vlan 100
13
802.1ah on ES+ NPU Overview
  802.1ah is implemented on ES+/7600 for first time on a Cisco
platform
  802.1ah utilizes both PFC/DFC ASIC and NPU to perform the 2
required layer2 switching decisions for dot1ah
  Dot1ah on ES+/7600 follows the IB Backbone Edge Bridge model
  PFC/DFC represents the B-component of the IB-BEB and switches
the packet towards the provider backbone port or NNI
  802.1ah (NPU) represents the I-component as well as the provider
instance port (tunnel engine) and switches the packet towards the
customer instance port or UNI
  PFD/DFC learns Backbone MAC addresses or B-MACs and floods
on Backbone VLANs or B-VLANs
  802.1ah (NPU) learns Customer MAC addresses or C-MACs and
floods on Customer bridge-domains or C-BDs
14
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
15
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
7600 – PBB IB-BEB Logical Flow
7600
Ingress
C-MAC1
Egress
ISID-1
B-MAC1
Port,
802.1q or
802.1ad
(QinQ)
EFP
Service
instances
C-MAC2
ISID-2
VLAN local
EFP or switchports
with the B-VLANs
Significance per
Port
C-MAC3
ISID-3
VLAN tag
translation and
manipulation
C-MAC4
B-MAC2
ISID-4
802.1q/qinq/ 802.1ad
PBN
PBBN
AS
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
16
7600 – PBB IB-BEB Configuration
ELAN Service Implementation
Step 1
Ingress EFP configuration (UNI)
interface TenGigabitEthernet3/1
dot1q tunneling ethertype 0x88A8
service instance 100 ethernet
description ** UNI EFP - ELAN Service
encapsulation dot1q 100 second-dot1q 1-4094
rewrite ingress tag pop 1 symmetric
service-policy input vz-ingress-policer
service-policy output vz-H-QoS-parent
l2protocol forward
bridge-domain 100 c-mac
interface TenGigabitEthernet3/2
dot1q tunneling ethertype 0x88A8
service instance 100 ethernet
description ** UNI EFP - ELAN Service
encapsulation dot1q 100 second-dot1q 1-4094
rewrite ingress tag pop 1 symmetric
service-policy input vz-ingress-policer
service-policy output vz-H-QoS-parent
l2protocol forward
bridge-domain 100 c-mac
Step 2
Mac-in-Mac tunnel configuration
ethernet mac-tunnel virtual 1
description ** IB-BEB - Mac Tunnel 1
bridge-domain 1000
service instance 1 ethernet
description ** ELAN Service - ISID
encapsulation dot1ah isid 10000
bridge-domain 100 c-mac
Step 3
Egress EFP configuration (NNI)
interface TenGigabitEthernet3/3
dot1q tunneling ethertype 0x88A8
service instance 1 ethernet
description ** B-VLAN - MAC Tunnel 1
encapsulation dot1q 1000
rewrite ingress tag pop 1 symmetric
service-policy output vz-core-queuing
bridge-domain 1000
or
Egress switchport configuration (NNI)
interface TenGigabitEthernet3/3
switchport
switchport mode trunk
switchport allowed vlan 1000
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
17
7600 – MPLS + 802.1ah IB-BEB Logical Flow
Ingress
C-MAC1
Egress (ES
+40)
ISID-1
VPWS (P2P) Pseudowire
B-MAC1
C-MAC2
Port,
802.1q or
802.1ad
(QinQ)
EFP
Service
instances
ISID-2
MPLS Interface/
Sub-interfaces
C-MAC3
ISID-3
VLAN tag
translation and
manipulation
C-MAC4
MPLS Transport
Network
(H)-VPLS Pseudowire(s)
B-MAC2
ISID-4
VFI
VPWS (P2P) Pseudowire
802.1q/qinq/ 802.1ad
PBN
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
AS
18
7600 – MPLS + PBB IB-BEB Configuration
VPWS + 802.1ah Service Implementation
Step 1
Ingress EFP configuration (UNI)
interface TenGigabitEthernet3/1
dot1q tunneling ethertype 0x88A8
service instance 100 ethernet
description ** UNI EFP – VPWS Service
encapsulation dot1q 100 second-dot1q 1-4094
rewrite ingress tag pop 1 symmetric
service-policy input vz-ingress-policer
service-policy output vz-H-QoS-parent
l2protocol forward
bridge-domain 100 c-mac
Step 2
Mac-in-Mac tunnel configuration
ethernet mac-tunnel virtual 1
description ** IB-BEB - Mac Tunnel 1
bridge-domain 1000
service instance 1 ethernet
description ** VPWS Service - ISID
encapsulation dot1ah isid 10000
bridge-domain 100 c-mac
Step 3
VPWS configuration
interface Vlan1000
description ** IB-BEB – VPWS Service
xconnect 2.2.2.2 3000 encapsulation mpls
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
19
7600 – MPLS + PBB IB-BEB Configuration
VPLS + 802.1ah Service Implementation
Step 1
Ingress EFP configuration (UNI)
interface TenGigabitEthernet3/1
dot1q tunneling ethertype 0x88A8
service instance 100 ethernet
description ** UNI EFP – VPLS Service
encapsulation dot1q 100 second-dot1q 1-4094
rewrite ingress tag pop 1 symmetric
service-policy input vz-ingress-policer
service-policy output vz-H-QoS-parent
l2protocol forward
bridge-domain 100 c-mac
interface TenGigabitEthernet3/2
dot1q tunneling ethertype 0x88A8
service instance 100 ethernet
description ** UNI EFP - VPLS Service
encapsulation dot1q 100 second-dot1q 1-4094
rewrite ingress tag pop 1 symmetric
service-policy input vz-ingress-policer
service-policy output vz-H-QoS-parent
l2protocol forward
bridge-domain 100 c-mac
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
Step 2
Mac-in-Mac tunnel configuration
ethernet mac-tunnel virtual 1
description ** IB-BEB - Mac Tunnel 1
bridge-domain 1000
service instance 1 ethernet
description ** VPWS Service - ISID
encapsulation dot1ah isid 10000
bridge-domain 100 c-mac
Step 3
VPLS configuration
l2 vfi Vz-MAC-Tunnel-1 manual
vpn id 3000
neighbor 2.2.2.2 encapsulation mpls
neighbor 3.3.3.3 encapsulation mpls
interface Vlan1000
description ** IB-BEB – VPLS Service
xconnect vfi Vz-MAC-Tunnel-1 manual
20
Flexible Ethernet Edge for .1ah
 
The Cisco implementation will provide for the services mandated by 802.1ah, and will
extend them to support all the following offerings:
 
S-Tagged Service
Multiplexed: Each S-VID maps to an I-SID. It is possible to retain or pop the STAG. (Retention of S-TAG is an extension of 802.1ah)
Bundled (same as 802.lah): Multiple S-VIDs map to an I-SID. The S-TAG must
be retained
 
C-Tagged Service (extension of 802.1ah)
Multiplexed: Each C-VID maps to an I-SID. It is possible to retain or pop the CTAG.
Bundled: Multiple C-VIDs map to an I-SID. The C-TAG must be retained.
 
S/C-Tagged Service (extension of 802.1ah)
Multiplexed: Each S-VID/C-VID pair maps to an I-SID. It is possible to retain or
pop the S-TAG only or both S-TAG/C-TAG pair.
Bundled: Multiple S-VID/C-VID pairs maps to an I-SID. The S-TAG/C-TAG pair
must be retained.
 
Port Based Service (same as 802.1ah): All frames are mapped to the same I-SID.
All tags, if any, are retained.
21
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
PBB IB-BEB Packet Flow
CE Side
PBBN Side
S-tagged Service - Multiplexed
C-DA
C-SA S-TAG C-TAG 0x800
Data
or
B-DA
B-SA B-TAG I-TAG C-DA
B-DA
B-SA B-TAG I-TAG
B-DA
B-SA B-TAG I-TAG C-DA
C-DA
C-SA S-TAG C-TAG 0x800
C-SA C-TAG 0x800
Data
Data
S-tagged Service - Bundled
C-DA
C-SA S-TAG C-TAG 0x800
Data
C-SA S-TAG C-TAG 0x800
Data
C-tagged Service - Multiplexed
C-DA
C-SA C-TAG 0x800
Data
or
B-DA
B-SA B-TAG I-TAG
C-DA
C-SA C-TAG 0x800
B-DA
B-SA B-TAG I-TAG
C-DA
C-SA
B-DA
B-SA B-TAG I-TAG
C-DA
C-SA C-TAG 0x800
0x800
Data
Data
C-tagged Service - Bundled
C-DA
C-SA C-TAG 0x800
Data
Data
S/C-tagged Service - Multiplexed
C-DA
C-SA S-TAG C-TAG 0x800
Data
or
or
B-DA
B-SA B-TAG I-TAG C-DA
C-SA S-TAG C-TAG 0x800
B-DA
B-SA B-TAG I-TAG
C-DA
C-SA C-TAG 0x800
B-DA
B-SA B-TAG I-TAG
C-DA
C-SA
B-DA
B-SA B-TAG I-TAG C-DA
B-DA
B-SA B-TAG I-TAG
0x800
Data
Data
Data
S/C-tagged Service - Bundled
C-DA
C-SA S-TAG C-TAG 0x800
Data
C-SA S-TAG C-TAG 0x800
Data
Port Based Service
C-DA
Presentation_ID
C-SA
…
© 2006 Cisco Systems, Inc. All rights reserved.
C-DA
C-SA
…
22
MAC Address Scalability in H-VPLS
H-VPLS
H-VPLS with PBB
IP/MPLS
IP/MPLS
IP/MPLS
c-mac
c-mac
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
c-mac
Presentation_ID
IP/MPLS
c-mac
c-mac
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
c-mac
© 2006 Cisco Systems, Inc. All rights reserved.
c-mac
c-mac
:
:
:
:
:
c-mac
b-mac
b-mac
:
b-mac
 
 
b-mac
b-mac
:
b-mac
c-mac
c-mac
:
:
:
:
:
c-mac
No customer MAC addresses
on N-PE nodes
N-PEs only learn backbone
MAC addresses imposed by
U-PEs
23
Deployment Scenario:
H-VPLS extension + 802.1ah
802.1Q
CE
VPWS/
H- VPLS w/
802.1ah
C-VLAN
uPE/
IB-BEB
CE
VPWS
VPWS/
H- VPLS w/
802.1ah 802.1ad/Q-in-Q
VPWS/VPLS
uPE/
IB-BEB
nPE
nPE
VPWS
VPWS
VSI
VPWS/VPLS
IP/MPLS Core
CE
BEB
I-SID
nPE
VSI
nPE
uPE/
IB-BEB
I-SID
E-Line Service
uPE/
IB-BEB
E-LAN Service
S-VLAN
CE
802.1ad/Q-in-Q
VSI
CE
S-VLAN
uPE/
IB-BEB
I-SID
CE
CE
VPWS
CE
802.1ad/ Q-in-Q
S-VLAN
CE
CE
S-VLAN
MPLS
Access
Presentation_ID
Aggregation
© 2006 Cisco Systems, Inc. All rights reserved.
Core Transport
Aggregation
Access
24
Scalability
Scalability Factor
Scalability Number
Total number of EVCs in the system
32000
Total number of EVCs per linecard
16000
Total number of ISIDs in the system
Total C-MAC addresses per LC
16M
128000 (32000 per NPU)
Total number of EVCs per ISID per NPU
110
Total number of EVCs per ISID for a two port Excalibur
220
Total number of EVCs per ISID for a four port Excalibur
440
Total B-bridge-domains per chassis
4094
Total I-SIDs or MAC-Tunnels
16000
Total entries in a C-MAC table
32000
25
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
26
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Test: Verify PCP Propagation and Queuing Behavior for ELAN
Service Using UNI Ingress 2R3C Policer Marking
IXIA
Sniffer
Ten3/3
L2 Link
Ten3/1
PE1Ten3/2
IB BEB
2R3C Queuing, etc..
Policer
ES2
IXIA
C-DA
C-SA
S-Tag, CoS=1
C-Tag, CoS =2
C payload
FCS
1. 
2. 
Ten3/4
MPLS Link
On PE1-IB_BEB
Ten1/0/1
IXIA
Ten1/0/0
ES1
ES3
IXIA
Ten3/3
L2 Link
Ten3/1
P-
PE2-
BCB
IB-BEB
Ten3/2
Ten3/4
MPLS Link
B-DA
ES4
B-SA
IXIA
B-Tag,
CoS=3,4,5
I-Tag, CoS=3,4,5
C-DA
C-SA
C-Tag, CoS =2
C-DA
C-SA
S-Tag,
CoS=3,4,5
C-Tag, CoS =2
C payload
FCS
C payload
FCS
 
Ingress card frames are remarked to CoS 5,4,3 by 2R3C Policer
 
Egress card frames are sent to separate queues based on Policer marking for Queuing, etc ….
Show end-2-end remarked CoS mapping in PBB frame and Egress PE2-IB_BEB
 
Presentation_ID
Sniffer capture to show COS is mapped from S-TagI-TagB-Tag and back to egress S-Tag
© 2006 Cisco Systems, Inc. All rights reserved.
27
References
  IEEE 802.1ah - Provider Backbone Bridges, Draft 4.2, April 2008.
  “VPLS Interoperability with Provider Backbone Bridges”, draftsajassi-l2vpn-vpls-pbb-interop-04-txt, March 2009.
  “Extensions to VPLS PE model for Provider Backbone”, Bridging
draft-balus-sajassi-l2vpn-pbb-vpls-00.txt, March 2009.
  “Provider Backbone Bridging and MPLS: Complementary
Technologies for Next-Generation Carrier Ethernet Transport”, S.
Salam and A. Sajassi, IEEE Communications Magazine, Vol. 46,
No. 3, March 2008.
  “The Evolution of Carrier Ethernet Services – Requirements and
Deployment Case Studies’, L. Fang, N. Bitar, R. Zhang, and M.
Taylor, IEEE Communications Magazine, Vol. 46, No. 3, March
2008.
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
28
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
29
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
L2 Convergence
 
EVC L2 Convergence - SRD and before
MST (BPDU relay, switchport, EVC)
REP (switchport)
PW Redundancy (MPLS aggregation)
Flex-Link
Etherchannel/LACP (single-homed devices)
Interface-Backup (single-homed devices)
 
New features in SRE
MST AG – simplify MST based deployments
REP – support for EVC added
mLACP – dual homed LACP
30
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
30
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
31
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Why MST Access Gateway?
  Avoid running full Spanning Tree protocol on NPE – STP is
challenging to troubleshoot
  Terminate multiple Ethernet access rings running MST on NPE without
running full STP
  Each ring can have its own independent topology
  Isolate topology changes/MAC flushes localized to each ring
  Improve scalability
  No full STP processes on NPE routers
  Maintain existing STP topologies on the access networks
  Access nodes just speak regular MSTP/RSTP
  Platform Support
  ASR9K – since FCS
  7600 – 12.2SRE
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
32
MST AG operation
SRE
  MST AG ports send preconfigured BPDU’s with root or zero cost to root information towards
access network. Access network sees a loop because of root reachability from both NPE’s.
  Both NPE’s can send the same information or arbitrarily can be set as best and second best
bridge via priority or cost setting for load balancing purposes
  Root bridge can be one of the NPE’s or arbitrarily set non-existent bridge address
  MST AG ports are always in Designated state and are forwarding
  L2 domain runs regular MST protocol. All convergence operations and port state transitioning
happen in the access network.
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
33
MST AG TCN Propagation
  NPE’s snoop and relay TCN from BPDU received from access network
  NPE’s trigger MAC withdrawal to neighbors
  TCN is forwarded only to the port within the same MST AG group thus providing L2
domains isolation
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
34
Access Network Failure Scenarios
  Failure Scenarios 1,2 and 3 cause a primary data path disruption
  UPE-2 BPDU on Atlernate Port is has now the best BPDU – port transitions to root port
role and forwarding state and data path is restored
  TCN propagates across L2 domain and is relayed between NPE’s
  NPE’s trigger MAC withdrawal
‘
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
35
Root Port Recovery
  When root bridge recovers it starts sending best BPDU towards the access network and
convergence to the original path occurs
  Sending of the best BPDU has to be delayed to allow core convergence; e.g. if the router was
reloaded
  7600 router runs STP state machine on MST AG when the port is coming from down to up state.
The ports is going through LST-LRN-FWD states. To disable this behavior spanning tree port
fast has to be configured on MST AG ports. BPDU’s are sent immediately upon port recovery
which can cause traffic black-hole if core has not converged. EEM can be used to delay port-up
event under certain scenarios.
  ASR 9K does not run spanning tree state machine and defines a dedicated timer to delay the
best BPDU generation.
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
36
NPE isolation failure scenario
  N-PE isolation occurs if all core facing interfaces are not available resulting in VPLS,
Psedowires or L3 connectivity failure
  N-PE isolation failure is not propagated into access interfaces therefore STP topology
remains unchanged, this results in traffic blackhole as access network continues
forwarding towards isolated PE
  An uplink tracking feature is under consideration for future releases
  Current solution is based on EEM – when router isolation is discovered the access
interfaces from redundant networks can be shut down which triggers MST convergence.
Upon recovery, timer can be set to delay access links recovery and avoid immediate
BPDU sending to the access network.
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
37
Using EEM for Uplink Tracking
Backbone uplink on NPE-1 is going down
event manager applet Backbone-DN
event syslog pattern "%LINK-3-UPDOWN: Interface GigabitEthernet1/40, changed s"
action 1.0 cli command "enable"
action 1.1 cli command "conf t"
action 1.2 cli command "int g1/31"
action 1.3 cli command "sh”
Backbone uplink on NPE-1 is going up
event manager applet Backbone-UP
event syslog pattern "Interface GigabitEthernet1/40, changed state to up"
action 1.0 cli command "enable"
action 1.1 cli command "conf t"
action 1.2 cli command "int g1/31"
action 1.3 cli command "no sh”
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
38
Special PW failure scenario
  Special PW failure can be result of PE isolation or a miss-configuration
  Unlike MST, R-L2GP special PW failure does not cause a loop and therefore does not
cause permanent traffic loss because BPDU forwarding topology remains unchanged
and is not affected by this failure
  TCN will not be relayed between the two NPE’s – MAC flush may not happen in a part of
L2 domain which may cause temporary traffic loss until MAC aging occurs. Bidirectional
traffic will be restored immediately.
  MAC withdrawal will still be generated by the NPE receiving TCN
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
39
EVC STP Modes Comparison
STP mode
EVC
Support
RPVST/
PVST
NO
BPDU relay only
VLAN-STP
mapping
Per VLAN
Dynamic
Port State
N/A
Dynamic
BPDU
always FWD
N/A
MST
MST AG
SRD
SRE
Single MST Region
Single MST Region
VLAN to Instance mapping
applies to all ports
VLAN to Instance mapping applies to
all ports
YES
YES
NO
Designated ports, always forwarding
NO
preconfigured BPDU’s
YES
TCN
isolation
YES
NO
TCN forwarded between ports within
the same L2GP group
MAC
Withdrawal
NO
YES
YES
Complexity
Medium
High
Low
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
Prone to miss-configuration
40
MST AG configuration steps
1.  Configure MST parameters
 
 
MST AG reuses global MST configuration template to construct BPDU’s. To
insure proper MST function, parameters like name, revision and timers should
match on other bridges.
Note: due to single domain support the same MST parameters will be used on
all MST AG groups. In particular IST to VLAN mapping.
spanning-tree mode mst
spanning-tree mst configuration
name c7600
revision 1
instance 1 vlan 3500-3599
spanning-tree mst hello-time 1
spanning-tree mst forward-time 4
spanning-tree mst max-age 6
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
41
MST AG configuration steps
2. Configure MST AG Pseudo-Information (NPE-1)
spanning-tree pseudo-information transmit 1
remote-id 2
! use the number of pseudo-information of the peer router
mst 0-1 root 24576 001e.f7f6.6040
! root bridge and priority that will be send in BPDU on MST AG ports
3. Assing MST AG Pseudo-Information to a port
interface GigabitEthernet1/32
no ip address
spanning-tree portfast trunk
spanning-tree pseudo-information transmit 1
! the port will send preconf. BPDU’s as per MST global and pseudo-inf. gr. 1 conf.
service instance 3500 ethernet
encapsulation dot1q 3500
rewrite ingress tag pop 1 symmetric
bridge-domain 3500
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
42
MST AG configuration steps
  Configure Special PW for TCN relay
  This is the same configuration step as for MST BPDU relay
interface Vlan1
no ip address
xconnect vfi BPDU
end
NPE-1#sh run | sec BPDU
l2 vfi BPDU manual
vpn id 1
forward permit l2protocol all
neighbor 10.1.1.6 encapsulation mpls
  Configure Service Instances and Bridge Domains
  Configure all Egde Ports explicitly with “portfast” feature
  avoid LRN/LSTN states when bridge is converging
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
43
MST AG configuration validation
NPE-1# sh spanning-tree mst 1
##### MST1
Bridge
Root
vlans mapped:
3500-3599
address 001e.f7f6.6040 priority
this switch for MST1
Interface
---------------Gi1/1
Gi1/32
PW 10.1.1.6:1
Role
---Desg
Desg
Desg
Sts
--FWD
FWD
FWD
Cost
--------20000
20000
200
32769 (32768 sysid 1)
Prio.Nbr
-------128.1
128.32
128.55
Type
-------------Edge P2p
P2p R-L2GP
P2p R-L2GP
NPE-1#sh spanning-tree pseudo-information 1 configuration
Pseudo id 1, type transmit:
remote_id 2
mst_region_id 0, port_count 1, update_flag 0x0
mrecord 0x1A6BE02C, mrec_count 2:
msti 0: root_id 24576.001e.f7f6.6040, root_cost 0, update_flag 0x0
msti 1: root_id 24577.001e.f7f6.6040, root_cost 0, update_flag 0x0
NPE-1# sh spanning-tree pseudo-information 1 interfaces
Pseudo id 1:
GigabitEthernet1/32
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
44
Other useful commands
  on RP
sh spanning-tree mst configuration!
sh spanning-tree details!
sh vlan id 3500!
  on SP
deb spanning-tree pseudo-information!
debug spanning-tree bpdu!
deb spanning-tree mstp tc!
deb spanning-tree mstp flush !!
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
45
MST AG Restrictions
  Supported on ES+ and ES20
  Applicable to EVC with Bridge Domain only
No xconnect, connect or subinterface support
  No EVC untagged, priority tagged or default encapsulation support
Native VLAN is used for BPDU forwarding
  Single MST region support
All MST AG groups share MST Instance - VLAN mapping, name and
revision
  No MST boundary function (for RPVST/PVST/RSTP
interoperability)
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
46
7600 MST AG Scale
Feature
Scale
Comment
STP Regions
1
All R-L2GP groups have to use common MST
configuration; name, version, timers, IST-VLAN
mapping
MST
instances
64
As above
R-L2GP
groups
256
Ports in
No limit
R-L2GP group
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
All ports in a chassis can be assigned to a
single R-L2GP group
50,000 vport limit per chassis
47
ARS9K MST Access Gateway
Interface gig 0/0/0/10.1 l2
encap untagg
spanning-tree ring-termination ring1
preempt delay { until <hh:mm:ss> |
for <n> { hours |
minutes | seconds } }
interface GigabitEthernet0/0/0/10.1
name cisco
revision 1
bridge-id 0000.0000.0001
instance 0  I’m the root
root-id 0000.0000.0001
priority 4096
root-priority 4096
!
instance 1
vlan-ids 101,103,105,107
root-id 0000.0000.0002
priority 8192
root-priority 4096
!
instance 2  I’m the root
vlan-ids 102,104,106,108
root-id 0000.0000.0001
priority 4096
root-priority 4096
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
Access switch configuration
interface GigabitEthernet1/1/1
switchport mode trunk
spanning-tree mst 0,2 cost 100000
MST root for
instance 0,2
VFI
VFI
MST root for
instance 1
Access switch configuration
interface GigabitEthernet1/1/1
switchport mode trunk
spanning-tree mst 1 cost 100000
Interface gig 0/0/0/10.1 l2
encap untagg
spanning-tree ring-termination ring1
preempt delay { until <hh:mm:ss> |
for <n> { hours |
minutes | seconds } }
interface GigabitEthernet0/0/0/10.1
name cisco
revision 1
VFI
bridge-id
0000.0000.0002
instance 0
root-id 0000.0000.0001
priority
8192
VFI
root-priority 4096
!
instance 1  I’m the root
vlan-ids 101,103,105,107
root-id 0000.0000.0002
priority 4096
root-priority 4096
!
instance 2
vlan-ids 102,104,106,108
root-id 0000.0000.0001
priority 8192
root-priority 4096
48
Conclusions
MST AG provides an appealing option to operate STP
networks to service providers:
  Maintaining access networks without modification
  Lower maintenance complexity on N-PE’s – no full
spanning tree support
  Lower troubleshooting complexity on the network
STP isolation for L2 aggregation domains separated by
VPLS core
Deterministic root location
  Improvements from MST/EVC:
TCN isolation between access domains
More robust implementation, special PW failure does not
cause traffic black-hole
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
49
Agenda
  IEEE 802.1ah Technology and Benefits
  7600 Platform 802.1ah Architecture
  Implementing 802.1ah + VPWS/VPLS Services on 7600
  Implementing 802.1ah QoS on 7600
  L2 Convergence
  Overview and Evolution
  MST Access Gateway Concept
  mLACP
  Conclusions
50
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
mLACP
SRE
Standby POA
DHD
Virtual LACP Peer
Inter-chassis Communication
EtherChannel with mLACP
Active POA
  mLACP provides a good mechanism for multi-chassis resiliency
  DHD is attached to a group of Points of Attachments which look like a
single node
  mLACP appears to DHD as a single 802.3ad LACP
  POA work in active/standby mode
  ICC exchanges redundancy information between chassis
  Links to standby PoA are in hot-standby state
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
51
ICCP Overview
  ICCP is implemented according to the standard draft-martini-pwe3iccp-00.txt
  ICCP is an extensible Protocol to synchronize event/states between
multiple chassis which are part of the redundant group.
  ICCP is a reliable protocol which runs over TCP
  ICCP PDUs are exchanged between Peers to keep the application state
consistent across Routers.
  Control Messages to setup, notify and exchange heartbeats.
  Data Messages to exchange the application state consistent across the
chassis. Ex: LACP Parameters
  ICCP failure detection
ICC Heartbeat  Slow (~ 30 sec)
/32 Next-hop Tracking  Depends on IGP timers
BFD  ~50 – 150 msec
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
52
Pseudowire Redundancy in SRE
  VCCV over Primary and Backup PW
  Preferential Forwarding status bit according to
draft-ietf-pwe3-redundancy-bit
  Upon Receipt of PW switchover status request, The receiver
should clear the preferential status forwarding bit and activate the
PW.
  Back up Pseudowire will be preprovisioned in the data plane.But
forwarding is disabled.
  Supported with Scale EoMPLS configuration only.
  VPLS Redundancy is supported only with mLACP configuration.
  Supported on ES40,ES20 only.
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
53
mLACP with two sided VPWS/VPLS
redundancy
MPLS
L2
Standby
PE1
Standby
PW 2
Active
PW 1
Standby
L1
Active
Active
PE3 E Active
L3
PE2
Active
Active
PW 3
DHD1
SRE
Standby
PW 4
L4
PE4
Standby DHD2
Standby
  VPWS
Two PEs form one virtual group on each site, one PE is primary the other is backup
PE’s send primary/backup information during PW signaling
PW with both sides status <active> are established, others are hot standby
MPLS uplinks, attachment circuits and PW status tracking
Message exchange within virtual group (for mLACP it is ICC) with redundancy
status
  VPLS
PW will be active between PE’s with active access circuits only
Single active path through VPLS domain between PE virtual group
  Similar model applies to REP access
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
54
Pseudowire Redundancy
Two-way
PE1
IP/MPLS
Prim.
Primary
Pseudowire
PE2a
Prim.
CE1
CE2
ICCP
ICCP
LACP
Back.
IP or MPLS
PE2b
Redundant
Pseudowires
ICCP = Inter-Chassis Control Protocol
LACP
Back.
LACP = Link Aggregation Control Protocol
  Failures within MPLS network are protected by MPLS FRR
  Failures of Ethernet Attachment Circuits or PE handled by two-way PW redundancy
(Note: both sides of the PW are protected)
  Inter-Chassis Control Protocol (ICCP) for synchronization of redundancy state control for
LACP and PW redundancy
  Synchronization of state (active/standby) between the ACs and PWs
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
55
Pseudowire Redundancy
Two-way
PE1
IP/MPLS
Prim.
Primary
Pseudowire
PE2a
Prim.
CE1
CE2
ICCP
ICCP
LACP
Back.
IP or MPLS
PE2b
Redundant
Pseudowires
ICCP = Inter-Chassis Control Protocol
LACP
Back.
LACP = Link Aggregation Control Protocol
  Failures within MPLS network are protected by MPLS FRR
  Failures of Ethernet Attachment Circuits or PE handled by two-way PW redundancy
(Note: both sides of the PW are protected)
  Inter-Chassis Control Protocol (ICCP) for synchronization of redundancy state control for
LACP and PW redundancy
  Synchronization of state (active/standby) between the ACs and PWs
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
56
Pseudowire Redundancy
Two-way
PE1
IP/MPLS
Prim.
Primary
Pseudowire
PE2a
Prim.
CE1
CE2
ICCP
ICCP
LACP
Back.
IP or MPLS
PE2b
Redundant
Pseudowires
ICCP = Inter-Chassis Control Protocol
LACP
Back.
LACP = Link Aggregation Control Protocol
  Failures within MPLS network are protected by MPLS FRR
  Failures of Ethernet Attachment Circuits or PE handled by two-way PW redundancy
(Note: both sides of the PW are protected)
  Inter-Chassis Control Protocol (ICCP) for synchronization of redundancy state control for
LACP and PW redundancy
  Synchronization of state (active/standby) between the ACs and PWs
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
57
mLACP CLI
  Interchassis Redundancy Group
redundancy
interchassis group 1
member ip 10.12.1.33
! this is IP-address of opposite end of direct link between NPE-1/2
backbone interface GigabitEthernet1/40
mlacp system-priority 100
mlacp node-id 0
! monitor peer [bfd | route-watch]
  Pseudowire Class to reflect or decouple AC and PW status
pseudowire-class HS-PW
encapsulation mpls
status peer topology dual-homed
!This command reflects AC circuit status on all PWs
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
58
mLACP CLI (cont)
  Port-Channel Definition
interface Port-channel1
description mLACP
no ip address
lacp fast-switchover
lacp max-bundle 1
mlacp lag-priority 100
mlacp interchassis group 1
service instance 3701 ethernet
encapsulation dot1q 3701
xconnect 10.1.1.1 3701 pw-class HS-PW
backup peer 10.1.1.4 3701 pw-class HS-PW
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
59
Platform Specifics for mLACP
  mLACP is SSO Aware
  mLACP is only supported with EVC configuration.
No support for Subinterfaces, Access subinterfaces, Switchport configurations.
  mLACP is only supported with ES20,ES40
  mLACP is not supported with EVC Routed Pseudowire
configuration
Exception is inter-POA Routed PW use case for VRRP/HSRP
  Number of chassis part of redundancy group is 2
  802.1ah supports only 1 member link on the Port-Channel. mLACP
configuration should be active-standby with 1 member link.
  ASR9K target for mLACP is in release 4.0
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
60
Attachment Circuit Redundancy Options
summary
  STP based solution can’t provide sub second convergence time
and is difficult to support
  REP is simple, spanning tree free protocol and can coexist with
spanning tree topologies. REP integration with EVC in SRE.
  Etherchannel / LACP provides a good link redundancy scheme for
single homed devices, supported with EVC starting from SRC
  mLACP will provide good redundancy scheme for dual homed
devices.
Hot-standby PW synchronization with mLACP and REP will be
required
Presentation_ID
© 2006 Cisco Systems, Inc. All rights reserved.
61
Reference
1. 
LDP Specification - RFC3036
2. 
Pseudowire Setup and Maintenance Using
the Label Distribution Protocol (LDP) RFC4447
3. 
PWE3 - RFC 3985
4. 
Inter-Chassis Communication Protocol (ICCP)
to synchronize multi-chassis LACP and PW
redundancy state - draft: pwe3-iccp
5. 
Pseudowire Virtual Circuit Connectivity
Verification (VCCV) - RFC5085
6. 
Bidirectional Forwarding Detection (BFD) for
the Pseudowire Virtual Circuit Connectivity
Verification (VCCV) draft-ietf-pwe3-vccv-bfd-03
7. 
Pseudo Wire (PW) OAM Message Mapping draft-ietf-pwe3-oam-msg-map-09
62
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Questions & Answers
63
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
64
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Backup Slides
CIscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
65
Pseudowire Operation - Creation
  IGP = transport infrastructure
  Targeted LDP for L2VPN
  PW creation:
PW Label Withdrawal
It will result in the Label Mapping Message being advertised only if the
attachment circuit is active
PW Status TLV
Mapping for primary and and backup, but using TLV Status for detection
66
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
PW Status
1.  Until the SRC: when the AC associated with a PW is down (or
being held down for PW redundancy) labels advertised to peers
are withdrawn.
2.  RFC4447 specifies extensions for LDP which allow PW status to
be carried in notification messages to peers. This diverges LDP
label mappings from the AC status notification and allows labels
to be retained through AC status changes:
- as soon as the xconnect is provisioned,
- and until the xconnect is unprovisioned or AC interface shutdown.
3. 
The router can send pseudowire status to a peer router, even when the
attachment circuit is down
interface Loopback0 !
ip address 10.1.1.1 255.255.255.255 !
! !
Router# show mpls l2transport vc detail
pseudowire-class atomstatus !
…
encapsulation mpls !
Last remote LDP TLV status rcvd: AC DOWN(rx,tx faults)
status !
! !
interface GigabitEthernet10/5 !
xconnect 10.1.1.2 123 pw-class atomstatus !
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
67
Virtual Circuit Connectivity Verification
  Pseudowire VCCV
Control channel between a pseudowire's ingress and egress points over
which connectivity verification messages can be sent
Encapsulated using PWE3, follows data paths
  Control Channel (CC) Types
in-band, out-of-band, …
  Connectivity Verification (CV) Types
LSP Ping [RFC4379], ICMP Ping [RFC0792], BFD
  Can additionally carry fault detection status between the
endpoints of the PW
Translated into the native OAM status codes used by the native access
technologies
68
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public
Pseudowire - Detection, Notification
1.  VCCV-BFD Connectivity Verification
fault detection only
1.  LDP status TLV
mechanism for AC and PW status and defect notification
1.  PW OAM Message Mapping
specifies the mapping and notification of defect states
between a Pseudo Wire and the Attachment Circuits (AC)
of the end-to-end emulated service
69
CiscoEXPO
© 2010 Cisco Systems, Inc. All rights reserved.
Cisco Public