342-86400-498PS
Issue 1.2
April 2012
Page 143
Copyright
GE Multilin Inc. 2010-2012
6-bit TOS field in ingressing frames' IP packets (see Appendix C).
User-configured default priority for other frames.
“Super-priority” is assumed for frames with user-specified EtherType value.
If the mapping priority for the port is forced (see below), the forced value is also
used as the source priority for all ingressing frames, except for those with the
matching EtherType.
Source priority is used for ingress frame prioritization in the “LAN” switch.
Priority Mappings
Mapping priority options are available per port (choice applies to all the frames
ingressing the port).
Mapping choices:
-
Forced to priority N (N=0,1…6). (Priority of all frames, except for the selected
EtherType ones, becomes N.)
-
Equal to the frame‟s source priority, except for the frames with source priority
7, which are mapped with priority 6.
Mapping priority 7 is assumed for frames with user-specified EtherType value.
Mapping priority is used for frame prioritization in the “WAN” switch.
Frames’ FCS bytes
The ingressing frames‟ FCS fields (a 4-byte “Frame Check Sequence” at the end
of each frame) are checked at ingress, recalculated for monitoring the inter-unit
(Line port) links, and recalculated for the egress port(s). (This is necessary due
to the frames‟ extra bytes added by the “LAN” switch.)
Defective frames are discarded (at both check points).
Input Rate Limiting
Each of the 8 ports is individually configurable to:
- none
- 128 kbit/sec
- 256 kbit/sec
- 512 kbit/sec
- 1 Mbit/sec