Redundant Lsps - Extreme Networks BlackDiamond 6800 MPLS Installation And User Manual

Configuring RSVP-TE
An explicit routed path is encoded using the explicit route object (ERO) and is
transmitted in the path message. The ERO consists of a list of subobjects, each of which
describes an abstract node. By definition, an abstract node can be an IPv4 Prefix, IPv6
Prefix, or an autonomous system (AS) number. ExtremeWare RSVP-TE supports IPv4
abstract nodes, only. They can be an IP prefix interface address or an OSPF router-id.
The /32 IP address may represent the OSPF router ID, direct interface, or loopback
address.
Received path messages with EROs that contain any other subobject type result in the
transmittal of an "Unknown object class" error message. All LSRs along the specified
path must support the inclusion of the ERO in the path message for an explicitly routed
path to be successfully set up.
All ERO subobjects describing the path must be defined by the ingress LER.

Redundant LSPs

Two methods are available for provisioning redundant RSVP-TE LSPs at the ingress
LER. The first uses the concept of secondary or backup LSPs and the second relies on
equal-cost LSP route metrics.
Redundant RSVP-TE LSPs can be configured to provide alternate paths in the event that
the primary path fails. Secondary paths are fully provisioned preestablished RSVP-TE
LSPs that are maintained as inactive TE /32 routes to the path endpoint. If the primary
path is torn down, the primary path TE /32 route is removed from the routing table,
and a TE /32 route representing one of the active secondary paths is installed as the
preferred path for the LSP. If multiple secondary are paths available, the secondary
path is randomly selected. If the primary path is reestablished, the primary path TE /32
route is reinstalled as the preferred path.
Stateful failovers can be managed by configuring only secondary paths for an LSP.
When no primary paths are configured for an LSP, a TE /32 route representing one of
the secondary paths is installed in the route table. If the secondary path fails, for which
a TE /32 route has been installed in the route table, another secondary TE /32 route
representing separate path is installed in the route table (provided one is configured
and active). Secondary path TE /32 routes remain the preferred route unless a primary
path is configured for the LSP, the active secondary path fails, or the active secondary
path is deleted. Thus, no switch-back to the original secondary path is performed if the
original secondary path fails and is later reestablished.
Parallel RSVP-TE LSPs can exist to the same endpoint. Parallel LSPs exist when
multiple paths are configured to the same egress LSR, with each LSP having a
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