Nortel SMC 2450, Implementation Manual

Page: 54 / 262

Page 54 of 260 Description
553-3001-225 Standard 1.00 May 2006
fingerprints can be difficult. If the SMC initially sets the phone fingerprints,
the new fingerprint overwrites both fingerprint locations. A subsequent
fingerprint update modifies only one of the fingerprints, thereby leaving two
different fingerprints that can be specified uniquely for the primary and
secondary devices.
Note: Nortel recommends that both SMC clusters share the same private
key, and hence fingerprint, in a geographically redundant configuration.
Engineering impact and limitations
Buffering
Buffering and moving larger packets and small packet performance could be
a limitation for high-end systems. Nortel estimates that the hardware provides
at least 100 megabytes (MByte) throughput for 100 byte packets or 125 kilo
packets per second (Kpps). This is sufficient to support more than 1000
concurrent calls, assuming 50 to 100 pps/call.
Security log rate limiting
In the following circumstances, the security and firewall logs can use many
system resources and degrade performance:
• logging is turned on for a rule that processes many packets per second
• the SMC is installed in an environment where there is much additional
traffic that is not handled by the current rules and logging is turned on for
unavailable messages
• the SMC is under certain types of attacks
• a message is logged for every packet
These circumstances can degrade the performance of the SMC. Modifying
logging configuration can help to overcome these issues. For more
information, see “Logging” on
page 207 .