Diff-Serv Traffic Engineering; Mapping Of Traffic To A Diff-Serv Lsp; Admission Control Of Classes - Alcatel-Lucent 7450 Manual

Diff-Serv Traffic Engineering

Diff-Serv Traffic Engineering
Diff-Serv traffic engineering provides the ability to manage bandwidth on a per Traffic
Engineering (TE) class basis as per RFC 4124. In the base traffic engineering, LER computes LSP
paths based on available BW of links on the path. Diff-Serv TE adds ability to perform this on a
per TE class basis.
A TE class is a combination of Class Type and LSP priority. A Class Type is mapped to one or
more system Forwarding Classes using a configuration profile. The operator sets different limits
for admission control of LSPs in each TE class over each TE link. Eight TE classes are supported.
Admission control of LSP paths bandwidth reservation is performed using the Maximum
Allocation Bandwidth Constraint Model as per RFC 4125.

Mapping of Traffic to a Diff-Serv LSP

An LER will allow the operator to map traffic to a Diff-Serv LSP through one of the following
methods:
1. explicit RSVP SDP configuration of a VLL, VPLS, or VPRN service
2. class-based forwarding in an RSVP SDP. The operator can enable the checking by RSVP
3. auto-bind-tunnel RSVP-TE option in a VPRN service
4. static routes with indirect next-hop being an RSVP LSP name

Admission Control of Classes

There are a couple of admission control decisions made when an LSP with a specified bandwidth
is to be signaled. The first is in the head-end node. CSPF will only consider network links that
have sufficient bandwidth. Link bandwidth information is provided by IGP TE advertisement by
all nodes in that network.
Another decision made is local CAC and is performed when the RESV message for the LSP path
is received in the reverse direction by a SR OS node in that path. The bandwidth value selected by
the egress LER will be checked against link bandwidth, otherwise the reservation is rejected. If
accepted, the new value for the remaining link bandwidth will be advertised by IGP at the next
advertisement event.
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that a Forwarding Class (FC) mapping to an LSP under the SDP configuration is
compatible with the Diff-Serv Class Type (CT) configuration for this LSP.
7450 ESS MPLS Guide