Zte ZXR10 5900E Product Description page 38

ZXR10 5900E Product Description
LSP cannot be protected by embedding. Automatic Bypass Tunnel is the simplified
manual configuration. When main LSP needs FRR protection, it automatically establish a
Bypass Tunnel to protect the main LSP.A single automatic Bypass tunnel can protect
multiple main LSP. Bypass Tunnel is usually idle, bearing no data services. If Bypass
tunnel needs to assume data forwarding task when it is protecting main LSP, enough
bandwidth should be configured. When link and node fails, if the interface is configured
with FRR fast reroute protection, the data can be automatically switched to protection link.
When the failure is recovered, the normal forwarding path will be re-established.
Usually it's necessary to deploy MPLS TE FRR in MPLS TE network. It is decided by the
features of MPLS TE. In pure IP network, when local failure occurs, LDP will initiate LSP
establishment to the upstream node if there's other available route. Failure protection
can be quickly implemented locally by this mechanism before the route change caused
by the failure spread to the whole network. In the MPLS network where TE is not
deployed, LDP is widely used to establish LDP by DU. When local failure occurs, LDP
will initiate LSP establishment to upstream node if there's other available route. Since
bandwidth, priority and link attribute related to TE are not considered, the possibility to
successfully establish LSP is comparatively large. Thus the process from failure to
recovery is short. However, in MPLS TE network, head node CSPF uses route
information reckons out all route in the domain. RSVP establishes LDP based on the
route. When there's local failure in the network, the whole LSP should be re-established.
And CSPF cannot reckon out valid path before the route change caused by the failure
spread to the head node. Besides, local failure may lead to re-establishment of multiple
LSP in the network. In this way, compared with pure IP network and the MPLS network
with no TE deployed, MPLS TE network may need longer time to recover from the local
failure. So we establish a backup LSP in MPLS TE network, initiate FRR, and take quick
switching when local failure occurs.
ZXR10 5900E supports MPLSTE service with the following features:

Using CSPF algorithm to calculate TE tunnel

TE FRR tunnel

CR-LSP tunnel

TE FRR and CR-LSP tunnel switchover less than 50ms
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