Alcatel-Lucent 7210 SAS-X - Page 105

Subscriber Services
7210 SAS-X, R6 OS Services Guide Page 105
mixed-lsp-mode
Syntax [no] mixed-lsp-mode
Context config>service>sdp
Description This command enables the use by an SDP of the mixed-LSP mode of operation. This command
indicates to the service manager that it must allow a primary LSP type and a backup LSP type in the
same SDP configuration. For example, the lsp and ldp commands are allowed concurrently in the
SDP configuration. The user can configure one or two types of LSPs under the same SDP. Without
this command, these commands are mutually exclusive.
The user can configure an RSVP LSP as a primary LSP type with an LDP LSP as a backup type. The
user can also configure a BGP RFC 3107 BGP LSP as a backup LSP type.
If the user configures an LDP LSP as a primary LSP type, then the backup LSP type must be an RFC
3107 BGP labeled route.
At any given time, the service manager programs only one type of LSP in the linecard that will
activate it to forward service packets according to the following priority order:
1. RSVP LSP type. One RSVP LSP can be configured per SDP. This is the highest
priority LSP type.
2. LDP LSP type. One LDP FEC will be used per SDP. 7210 SAS does not support LDP
ECMP.
3. BGP LSP type. One RFC 3107-labeled BGP prefix programmed by the service
manager.
In the case of the RSVP/LDP SDP, the service manager will program the NHLFE(s) for the active
LSP type preferring the RSVP LSP type over the LDP LSP type. If no RSVP LSP is configured or all
configured RSVP LSPs go down, the service manager will re-program the linecard with the LDP LSP
if available. If not, the SDP goes operationally down.
When a higher priority type LSP becomes available, the service manager reverts back to this LSP at
the expiry of the sdp-revert-time timer or the failure of the currently active LSP, whichever comes
first. The service manager then re-programs the linecard accordingly. If the infinite value is
configured, then the SDP reverts to the highest priority type LSP only if the currently active LSP
failed.
Note however, that LDP uses a tunnel down damp timer which is set to three seconds by default.
When the LDP LSP fails, the SDP will revert to the RSVP LSP type after the expiry of this timer. For
an immediate switchover this timer must be set to zero. Use the configure>router>ldp>tunnel-
down-damp-time command.
Note: For more information on, “configure>router>ldp>tunnel-down-damp-time” command, see
7210 SAS M, X OS MPLS Guide.
If the user changes the value of the sdp-revert-time timer, it will take effect only at the next use of the
timer. Any timer which is outstanding at the time of the change will be restarted with the new value.
In the case of the LDP/BGP SDP, the service manager will prefer the LDP LSP type over the BGP
LSP type. The service manager will re-program the linecard with the BGP LSP if available otherwise
it brings down the SDP operationally.
Also Note the following difference in behavior of the LDP/BGP SDP compared to that of an RSVP/
LDP SDP. For a given /32 prefix, only a single route will exist in the routing table: the IGP route or