Mpls And Rsvp; Figure 6: Lsp Using Rsvp Path Set Up - Alcatel-Lucent 7450 Manual

SFO
10.10.10.1
SFO
10.10.10.1
Figure 6
(ILER 1) transmits an RSVP path message (path: 30.30.30.1) downstream to the egress label edge
router (ELER 4). The path message contains a label request object that requests intermediate LSRs
and the ELER to provide a label binding for this path.
In addition to the label request object, an RSVP PATH message can also contain a number of
optional objects:
•
•
•
Upon receiving a path message containing a label request object, the ELER transmits a RESV
message that contains a label object. The label object contains the label binding that the
downstream LSR communicates to its upstream neighbor. The RESV message is sent upstream
towards the ILER, in a direction opposite to that followed by the path message. Each LSR that
processes the RESV message carrying a label object uses the received label for outgoing traffic
associated with the specific LSP. When the RESV message arrives at the ingress LSR, the LSP is
established.
7450 ESS MPLS Guide
PATH:30.30.30.1
1 2
RESV:10.10.10.1
label label
100|push 100|200|swap
1 2
100

Figure 6: LSP Using RSVP Path Set Up

displays an example of an LSP path set up using RSVP. The ingress label edge router
Explicit route object (ERO) — When the ERO is present, the RSVP path message is
forced to follow the path specified by the ERO (independent of the IGP shortest path).
Record route object (RRO) — Allows the ILER to receive a listing of the LSRs that the
LSP tunnel actually traverses.
A session attribute object controls the path set up priority, holding priority, and local-
rerouting features.
PATH:30.30.30.1 PATH:30.30.30.1
3
RESV:10.10.10.1
label
200|300|swap
3
200 300

MPLS and RSVP

NYC
30.30.30.1
4
RESV:10.10.10.1 RESV:10.10.10.1
label
300|pop
NYC
30.30.30.1
4
OSSG016
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