H3C Technologies H3C S6800 Series Switches - Manual (Page 92)

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node protection mode. Automatically created bypass tunnels can be used to protect any type of CT,
but they cannot provide bandwidth protection.
A primary tunnel can have both manually configured and automatically created bypass tunnels. The PLR
will select one bypass tunnel to protect the primary CRLSP. The selected bypass tunnel is bound to the
primary CRLSP.
Manually created bypass tunnels take precedence over automatically created bypass tunnels. An
automatically created bypass tunnel in node protection mode takes precedence over an automatically
created bypass tunnel in link protection mode. Among manually created bypass tunnels, the PLR selects
the bypass tunnel for protecting the primary CRLSP by following these rules:
1. Selects a bypass tunnel according to the principles, as shown in Table 2 .
2. Prefers the bypass tunnel in node protection mode over the one in link protection mode.
3. Prefers the bypass tunnel with a smaller ID over the one with a bigger tunnel ID.
Table 2 FRR protection principles
Bandwidth
required by
primary
CRLSP
Primary CRLSP
requires
bandwidth
protection or not
Bypass tunnel providing
bandwidth protection
Bypass tunnel providing no
bandwidth protection
0
Yes
The primary CRLSP cannot be
bound to the bypass tunnel.
The primary CRLSP can be bound to
the bypass tunnel if CT 0 or no CT is
specified for the bypass tunnel.
After binding, the RRO message
does not carry the bandwidth
protection flag. The bypass tunnel
does not provide bandwidth
protection for the primary CRLSP,
and performs best-effort forwarding
for traffic of the primary CRLSP.
No
None-zero Yes
The primary CRLSP can be bound
to the bypass tunnel when all the
following conditions are met:
• The bandwidth that the bypass
tunnel can protect is no less
than the bandwidth required
by the primary CRLSP.
• There is not a CT specified for
the bypass tunnel, or the
specified CT is the same as
that specified for the primary
CRLSP.
After binding, the RRO message
carries the bandwidth protection
flag, and the bypass tunnel
provides bandwidth protection for
the primary CRLSP.
The primary CRLSP prefers bypass
tunnels that provide bandwidth
protection over those providing no
bandwidth protection.
The primary CRLSP can be bound to
the bypass tunnel when one of the
following conditions is met:
• No CT is specified for the bypass
tunnel.
• The specified CT is the same as
that specified for the primary
CRLSP.
After binding, the RRO message
does not carry the bandwidth
protection flag.
This bypass tunnel is selected only
when no bypass tunnel that
provides bandwidth protection can
be bound to the primary CRLSP.