FCM9002 USER MANUAL
76-02-095 Rev.B
Page 111 of 145
4.5.2.2 VLAN Mode – CTag
In C-Tag mode, all user packets egress the WAN port with a C-Tag. Optionally ,
the FCM9002 may push/pop a single C-Tag to untagged only or all packets.
In C-Tag mode, the FCM9002 supports the full range of available VLAN ID’s in
the range 1-4095, but each ID may only be allocated to a single user port.
Packets ingressing already tagged will either pass unchanged, if the tag ID is
contained within a flow allocation or be discarded. They may also have an extra
tag pushed to form a QinQ frame.
The action taken on ingress of an untagged frame may be selected from
DISCARD, or push a default Tag.
4.5.3 Max Frame Size
The Maximum frame size may be defined for the FCM9002. The options for
packet size are
1522 Max size is 1518 bytes for untagged, and 1522 bytes for tagged frames.
2048 Maximum packet size is 2048Bytes
10k
Maximum packet size is 10k bytes
4.5.4 Priority Translation
When a port is pushing an S-Tag or C-Tag onto a previously untagged frame the
tag priority may be sourced from the IP DSCP marker. However, since DSCP
has 64 possible values and the Tag priority only has 8, a mapping is provided to
support the different traffic classes.
4.5.5 CFM Domains
The global CFM, Continuity and Fault Management configuration menus allow for
the configuration of the global parameters such as Maintenance Domains, MD
and also for viewing the status of the CFM connections
CFM uses Maintenance Domains to indicate the span of the circuit to be
monitored as shown below:
