HP MSR2000/3000/4000 Router Series MPLS Command Reference

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rsvp authentication window-size
Use rsvp authentication window-size to configure the RSVP authentication window size, which is the
maximum number of authenticated RSVP messages that can be received out of sequence on an interface.
Use undo rsvp authentication window-size to restore the default.
Syntax
rsvp authentication window-size number
undo rsvp authentication window-size
Default
Only one authenticated RSVP message can be received out of sequence on an interface.
Views
Interface view
Predefined user roles
network-admin
Parameters
number: Specifies the maximum number of authenticated RSVP messages that can be received out of
sequence, in the range of 1 to 64.
Usage guidelines
To protect against replay attacks, the sender places a unique sequence number in each RSVP message
that contains authentication information. The sender monotonically increases the value of the sequence
number each time it sends an RSVP message. If the sequence number of a received message is in the
specified authentication window size, the receiver accepts the message. Otherwise, the receiver discards
the message.
When the receiver receives an RSVP message, it compares the sequence number of the last accepted
RSVP message with the sequence number of the newly received RSVP message.
• If the new sequence number is greater than the last sequence number, RSVP accepts the message
and updates the last sequence number with the new sequence number.
• If the received sequence number equals the last sequence number, RSVP regards the message a
replay message and discards the message.
• If the new sequence number is smaller than the last sequence number but greater than the new
sequence number minus the window size, and has never been received before, RSVP accepts the
message. If the new sequence number has been received before, RSVP regards the message a
replay message and discards the message.
• If the new sequence number is smaller than the new sequence number minus the window size, RSVP
regards the message invalid and discards the message.
By default, the authentication window size is 1, namely, if the sequence number of a newly received RSVP
message is smaller than that of the last accepted message, the device discards the message. However,
if the sender sends multiple RSVP messages in a short time, these messages might arrive at the neighbor
out of sequence. If you use the default window size, the out-of-sequence messages will be discarded. To
solve this problem, you can use the rsvp authentication window-size command to configure a correct
window size.