Rsvp Objects; Label; Label Request; Explicit Route - Extreme Networks BlackDiamond 6800 MPLS Installation And User Manual

Traffic Engineering

RSVP Objects

This section describes the RSVP objects that are used to establish RSVP-TE LSPs:

• Label

• Label request

• Explicit route

• Record route

• Session attribute

Label
The label object is carried in the reservation message and is used to communicate a next
hop label for the requested tunnel endpoint IP address upstream to towards the sender.
Label Request
A label request object specifies that a label binding for the tunneled path is requested. It
also provides information about the network layer protocol that is carried by the tunnel.
The network layer protocol sent through a tunnel is not assumed to be IP and cannot be
deduced from the layer-2 protocol header, which simply identifies the higher layer
protocol as MPLS. Therefore, the layer-3 Protocol ID (PID) value must be set in the
Label Request Object, so that the egress node can properly handle the tunneled data.
Extreme switches only support the IP PID value (0x0800).
To create an RSVP-TE LSP, the sender on the MPLS path creates an RSVP path message
and inserts the label request object into the path message.
Explicit Route
The explicit route object specifies the route of the traffic as a sequence of nodes. Nodes
may be loosely or strictly specified.
The explicit route object is used by the MPLS sender if the sender knows about a route
that:
• Has a high likelihood of meeting the QoS requirements of the tunnel
• Uses the network resources efficiently
• Satisfies policy criteria
MPLS Module Installation and User Guide 5-9