SAVVIS allows customers to control certain traffic flows off-net with the implementation of community attribute values that prepend route/prefix paths with additional AS hops. These community attribute values, which the customer applies, affects the way SAVVIS peers choose the degree of preference of a given prefix/route, because the number of AS hops within the route-path has been lengthened.
The format for the second component of customer route community number (after 3561:) is set at five digits. This fixed length allows regular expressions to be used in applying a defined number of prepends to a given route/prefix path. This format is 3561:30PPN, where the fields are coded in the following way. (Note: The first 2 digits of the second component are always "30" then followed by variables of the "PP" and "N" variables which are defined in the following tables.)
The "PP" variable cross references peers of SAVVIS, defined in the following table. (Note, this will always be a two digit value.)
The "N" variable cross references the number of prepends,
defined in the following table. Please note, the only valid "N" value
for all peers (PP code 00) is 0 (Do not export).
N Values"N" Value Meaning
0 Do not export
1 Prepend once
2 Prepend twice
3 Prepend three times
9 Announce-only
Examples:
3561:30030 Do not export this route to PSINet (AS174)
3561:30142 Prepend this route twice, to UUNet (AS701)
3561:30159 Announce this route only to AT&T (AS7018)
For customers that have a host or block under a DDoS, the affected host/block can be advertised to AS3561 with community string 3561:666. This will cause all traffic to that host to be black-holed at the core of the AS3561 network. This action will trigger emails sent to the appropriate security and operations groups for notification purposes.
After advertising the prefix with 3561:666, the customer should open a priority one incident report with Client Services:
SAVVIS Support Center (SSC)
Phone: 888-638-6771email: ssc@savvis.net
Once the attack has been mitigated, the customer will be responsible for removing the prefix from being advertised.
SAVVIS will not be held responsible for customers who errantly advertise prefixes with the blackhole community string.