Path Message - Extreme Networks BlackDiamond 6800 MPLS Installation And User Manual

Figure 5-1: RSVP Messages
In addition to the path and reserve messages, RSVP has the following additional
message types:
• Path error message
• Reservation error message
• Path tear message
• Reserve tear message
• Reservation confirm message

Path Message

The RSVP path message is used to store state information about each node in the path.
Each RSVP sender periodically transmits a path message downstream along the route
for each data path. The path state includes, at minimum, the IP address of the previous
hop node. This IP address is used to route the reserve message on a hop-by-hop basis,
in the reverse direction.
In addition to the previous hop address, the path message contains the sender Tspec
and Adspec. The reservation message carries the flowspec.
MPLS Module Installation and User Guide
Previous Incoming
hops interfaces
Data
A
Path
Resv
B
Data
Path
Resv
B'
Outgoing
interfaces
Data
a c
Path
Router
Data
b d
Path
RSVP Elements
Next
hops
C
Resv
D
Resv
D'
MPLS_27
5-3