Additional Features
LAN-X Traffic Control Features
076R200-000
SpectraComm IP T1 Router Card
5-15
Issue 13
Installation and Operation Manual
Typical Expedited Traffic Application
Example:
It is desired to extend the LAN from a central site to a remote location using a T1 connection. The
LAN traffic is expected to be light to moderate with occasional sustained bursts for file transfers. It
is also desired to use VoIP between the remote site and the central site. VoIP must be given priority
to maintain quality voice service. (VoIP vendors typically mark their IP traffic for Expedited
Forwarding.)
A pair of SCIPs operating in LANX mode can be used to provide LAN extension between the
central site and remote site. When configured for Expedited Traffic Queuing, SCIP will provide
priority service to the VoIP traffic marked for expedited forwarding even during peak utilization
(file transfers) of normal traffic. If necessary, SCIP will drop normal traffic to provide the priority
service for VoIP.
SCIP’s built-in three-port Etherswitch will reduce unnecessary unicast LAN traffic. In addition,
SCIP’s MAC filtering will reduce unnecessary LAN broadcast traffic and provide security from
unauthorized PCs at the remote site trying to hack into the central site.
Special Considerations
•
SCIP expedited traffic queuing is supported only in LAN-X mode where Ethernets are
connected across a T1/E1 WAN providing transparent layer 2 connectivity.
•
SCIP can provide priority queuing for IPv4 and IPv6 packets marked with Differentiated
Services Codepoint for EF (Expedited Forwarding) value 0xB8. SCIP can also provide priority
queuing for another DSCP value other than 0xB8 if desired.
•
SCIP does not modify the DSCP value of any IP packet. It only compares the IP packet DSCP
value to the configured DSCP value.
•
A max rate may be configured for expedited traffic to ensure it does not completely overwhelm
normal priority traffic. Expedited traffic that is in violation of this rate limiting is left on the
Expedited Queue until the next available time window. This may result in dropped expedited
traffic if the sustained rate exceeds the configured max rate.
•
Expedited traffic queuing may be enabled or disabled. It is disabled by default. When expedited
traffic queuing is enabled, SCIP measures the peak expedited traffic rate as an aid to setting the
max rate parameter.
Содержание SpectraComm IP T1
Страница 119: ......
Страница 120: ...The Best Connections in the Business...