
47
Figure 18 FRR link protection
•
Node
protection
—The PLR and the MP are connected through a device and the primary LSP
traverses this device. When the device fails, traffic is switched to the bypass LSP. As shown
in
, the primary LSP is Router A — Router B — Router C — Router D — Router E, and
the bypass LSP is Router B — Router F— Router D. Router C is the protected device.
Figure 19 FRR node protection
Deploying FRR
When configuring the bypass LSP, make sure the protected link or node is not on the bypass LSP.
As bypass LSPs are pre-established, FRR requires extra bandwidth. When network bandwidth is
insufficient, use FRR for crucial interfaces or links only.
DiffServ-aware TE
Diff-Serv is a model that provides differentiated QoS guarantees based on class of service.
MPLS TE is a traffic engineering solution that focuses on optimizing network resources allocation.
DiffServ-aware TE (DS-TE) combines them to optimize network resources allocation at a per-service
class level. For traffic trunks which are distinguished by class of service, this means varied
bandwidth constraints. Essentially, what DS-TE does is to map traffic trunks with LSPs, making each
traffic trunk traverse the constraints-compliant path.
The device supports these DS-TE modes:
•
Prestandard
mode
—Implemented by using Hewlett Packard Enterprise proprietary
mechanisms
•
IETF
mode
—Implemented according to RFC 4124, RFC 4125, and RFC 4127.
Basic concepts
•
Class
Type
(CT)
—A set of traffic trunks crossing a link that is governed by a specific set of
bandwidth constraints. DS-TE allocates link bandwidth, implements constraint-based routing,
and performs admission control for a traffic trunk according to the traffic trunk's CT. A given
traffic trunk belongs to the same CT on all links.