Processing And Merging - Alcatel-Lucent 7210 SAS M Service Manual

Pseudowire Redundancy Service Models
of processing packets for a VLL service received over any of the pseudowires which are up. This
is to avoid black holing of user traffic during transitions. The SR-Series standby node forwards
these packets to the active node bye the Inter-Chassis Backup pseudowire (ICB pseudowire) for
this VLL service. An ICB is a spoke SDP used by a MC-LAG node to backup a MC-LAG SAP
during transitions. The same ICB can also be used by the peer MC-LAG node to protect against
network failures causing the active pseudowire to go down.
Note that at configuration time, the user specifies a precedence parameter for each of
thepseudowires which are part of the redundancy set as described in the application in
Resilience for a Switched PW Path on page
pseudowire to forward packet to in case both pseudowires show active/active for the local or
remote status during transitions.
Only VLL service of type Epipe is supported in this application. Furthermore, ICB spoke SDP can
only be added to the SAP side of the VLL cross-connect if the SAP is configured on a MC-LAG
instance.

Processing and Merging

Endpoint "X" is operationally up if at least one of its objects is operationally up. It is down if all its
objects are operationally down.
If the SAP in endpoint "X" transitions locally to the down state, or received a SAP down
notification by SAP-specific OAM signal, the node must send T-LDP SAP down status bits on the
"Y" endpoint ICB spoke SDP only. Note that Ethernet SAP does not support SAP OAM protocol.
All other SAP types cannot exist on the same endpoint as an ICB spoke SDP since non Ethernet
SAP cannot be part of a MC-LAG instance.
If the ICB spoke SDP in endpoint "X" transitions locally to down state, the node must send T-LDP
SDP-binding down status bits on this spoke SDP.
If the ICB spoke SDP in endpoint "X" received T-LDP SDP-binding down status bits or
pseudowire not forwarding status bits, the node saves this status and takes no further action. The
saved status is used for selecting the active transmit endpoint object.
If all objects in endpoint "X" transition locally to down state, and/or received a SAP down
notification by remote T-LDP status bits or by SAP specific OAM signal, and/or received status
bits of SDP-binding down, and/or received status bits of pseudowire not forwarding, the node
must send status bits of SAP down over all "Y" endpoint spoke SDPs, including the ICB.
Endpoint "Y" is operationally up if at least one of its objects is operationally up. It is down if all its
objects are operationally down.
If a spoke SDP in endpoint "Y", including the ICB spoke SDP, transitions locally to down state,
the node must send T-LDP SDP-binding down status bits on this spoke SDP.
Page 160
152. The 7210 SAS node uses this to select which
7210 SAS M Services Guide
VLL