PBB Epipe
PBB Epipe
Epipe is a point-to-point Ethernet bridging service that forwards traffic from one customer site to another. When Epipe is required between two sites, only one pseudowire (PW) is required and one Service Access Point (SAP) or customer-facing port is required on each PE routers. As the incoming traffic on a PE router is to be forwarded to the remote PE router, MAC address learning is not required and hence, Epipe does not suffer from MAC explosion issue which is caused by the number of MAC addresses a PE router learns in VPLS.
There are 2 reasons why PBB is incorporated with Epipe service-
- PBB Epipe could be another service that a network can support if it already has PBB-VPLS. The B-domain (or B-VPLS) can be shared by PBB VPLS and PBB Epipe.
- Many Epipes in the I-domain can be associated to the same B-VPLS in the B-domain. Thus, B-VPLS can aggregate all Epipe service and hence reducing the number of pseudowires in the B-domain.
Like in PBB VPLS, the PBB Epipe solution has two domains- B-domain with B-VPLS instance(s) and I-domain with Epipe services. The only difference is that the I-component is point-to-point Epipe. In PBB Epipe, backbone destination MAC address (B-DA) is configured during Epipe creation. This B-DA is the MAC address of the remote PE router that terminates the Epipe service.
Figure 1 shows two customer sites connected via a PBB Epipe service. The traffic forwarding behavior of PBB Epipe is similar to Epipe and as described next with reference to figure 1.
- When the Epipe in customer domain receives traffic on local SAP on PE1 router, it performs PBB encapsulation with B-SA, B-DA and I-TAG information. The B-DA of PE2 router is configured in Epipe. The I-SID is either manually configured or derived from the Epipe Service ID. I-SID values must match at both ends. Then the Epipe forwards the traffic to PBB tunnel which is a B-VPLS instance.
- The B-VPLS instance performs learning and forwarding of traffic based on B-DA address. If the B-DA is known in the forwarding database, it is unicast to the remote PE2 router.
- When the remote PE2 router receives traffic, it learns the backbone MAC address of PE1 router (i.e. B-SA address of the PBB frame) and performs the I-SID lookup. The I-SID value identifies the local SAP for that Epipe service. The traffic is then decapsulated and forwarded to local SAP.
The following section provides detailed configuration of PBB Epipe. Note this configuration is based on Alcatel-Lucent CLI commands.
1. Configuring full mesh of SDPs on PE1 and PE2 routers to all PE routers that belong to B-VPLS instance 1000.
PE1 router:
A:PE1# configure service sdp 12 mpls create
A:PE1>config> service> sdp# info
far-end 10.0.0.2
description "SDP to PE2 router"
ldp
no shutdown
exit
A:PE1# configure service sdp 13 mpls create
A:PE1>config> service> sdp# info
far-end 10.0.0.3
description "SDP to PE3 router"
ldp
no shutdown
exit
PE2 router:
A:PE2# configure service sdp 21 mpls create
A:PE2>config> service> sdp# info
far-end 10.0.0.1
description "SDP to PE1 router"
ldp
no shutdown
exit
A:PE2# configure service sdp 23 mpls create
A:PE2>config> service> sdp# info
far-end 10.0.0.3
description "SDP to PE3 router"
ldp
no shutdown
exit
2. PBB configuration for B-VPLS on PE1 and PE2 routers.
PE1 router:
A:PE1# configure service pbb
A:PE1>config> service> pbb# info
source-bmac 00:00:00:00:00:01
mac-name "PE1_B_SA" 00:00:00:00:00:01
exit
PE2 router:
A:PE2# configure service pbb
A:PE2>config> service> pbb# info
source-bmac 00:00:00:00:00:02
mac-name "PE2_B_SA" 00:00:00:00:00:02
exit
3. Configuring Epipe service on PE1 and PE2 routers. The command force-qtag-forwarding allows 802.1p bits preservation. The tunnel ID should match B-VPLS Service ID.
PE1 router:
A:PE1# configure service epipe 100 customer 1 create
A:PE1>config> service> epipe# info
description "CE1_Customer"
service-mtu 2000
pbb
force-qtag-forwarding
tunnel 1000 backbone-dest-mac 00:00:00:00:00:02 isid 100
exit
service-name "Epipe_100"
sap 1/2/1 create
exit
no shutdown
PE2 router:
A:PE2# configure service epipe 100 customer 1 create
A:PE2>config> service> epipe# info
description "CE2_Customer"
service-mtu 2000
pbb
force-qtag-forwarding
tunnel 1000 backbone-dest-mac 00:00:00:00:00:01 isid 100
exit
service-name "Epipe_100"
sap 1/2/1 create
exit
no shutdown
4. Configuring B-VPLS instance on PE1 and PE2 routers. Note, this B-VPLS instance will be configured on PE3 router as well but it has no relevance to PBB Epipe of this example.
PE1 router:
A:PE1# configure service vpls 1000 customer 1 b-vpls create
A:PE1>config> service> vpls# info
description "B-VPLS 1000"
service-mtu 2022
remote-age 86400
stp
shutdown
exit
service-name "B-VPLS_1000"
mesh-sdp 12:1000
exit
mesh-sdp 13:1000
exit
PE2 router:
A:PE2# configure service vpls 1000 customer 1 b-vpls create
A:PE2>config> service> vpls# info
description "B-VPLS 1000"
service-mtu 2022
remote-age 86400
stp
shutdown
exit
service-name "B-VPLS_1000"
mesh-sdp 21:1000
exit
mesh-sdp 23:1000
exit