HP MSR2000 Configuration Manual page 93

Use bypass tunnels to protect only critical interfaces or links when bandwidth is insufficient. Bypass
•
tunnels are pre-established and require extra bandwidth.
Make sure the bandwidth assigned to the bypass tunnel is no less than the total bandwidth needed
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by all primary CRLSPs to be protected by the bypass tunnel. Otherwise, some primary CRLSPs might
not be protected by the bypass tunnel.
A bypass tunnel typically does not forward data when the primary CRLSP operates correctly. For a
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bypass tunnel to also forward data during tunnel protection, you must assign adequate bandwidth
to the bypass tunnel.
A bypass tunnel cannot be used for services such as VPN.
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• You cannot configure FRR for a bypass tunnel. A bypass tunnel cannot act as a primary CRLSP.
Make sure the protected node or interface is not on the bypass tunnel.
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After you associate a primary CRLSP that does not require bandwidth protection with a bypass
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tunnel that provides bandwidth protection, the primary CRLSP occupies the bandwidth that the
bypass tunnel protects. The bandwidth is protected on a first-come-first-served basis. The primary
CRLSP that needs bandwidth protection cannot preempt the one that does not need bandwidth
protection.
After an FRR, the primary CRLSP will be down if you modify the bandwidth that the bypass tunnel
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can protect and your modification results in one of the following:
The CT type changes.
The bypass tunnel cannot protect adequate bandwidth as configured.
FRR protection type (whether or not to provide bandwidth protection for the primary CRLSP)
changes.
Manually configuring a bypass tunnel
The bypass tunnel setup method is the same as a normal MPLS TE tunnel. This section describes only
FRR-related configurations.
To configure a bypass tunnel on the PLR:
Step
1. Enter system view.
2. Enter tunnel interface view of
the bypass tunnel.
3. Specify the destination address
of the bypass tunnel.
4. Configure the bandwidth and
the CT to be protected by the
bypass tunnel.
5. Return to system view.
6. Enter interface view of the
egress interface of a primary
CRLSP.
7. Specify a bypass tunnel for the
protected interface (the current
interface).
Command
system-view
interface tunnel tunnel-number
[ mode mpls-te ]
destination ip-address
mpls te backup bandwidth [ ct0 |
ct1 | ct2 | ct3 ] { bandwidth |
un-limited }
quit
interface interface-type
interface-number
mpls te fast-reroute bypass-tunnel
tunnel tunnel-number
84
Remarks
N/A
N/A
The bypass tunnel destination
address is the LSR ID of the MP.
By default, the bandwidth and the
CT to be protected by the bypass
tunnel are not specified.
N/A
N/A
By default, no bypass tunnel is
specified for an interface.