Comtech EF Data CDM-840 - Manual (Page 198)

CDM-840 Remote Router Revision 2
Appendix C MN-CDM840
C–6
C .4.3 Multiple VL AN Tagging S upport
The Advanced VSAT platform supports processing Ethernet packets with multiple stacked VLAN
tags, with the following limitations:
• At the CTOG-250, only the outermost VLAN ID is used for mapping to the appropriate
QoS Groups.
• In Trunking Mode, L2 Header Compression only compresses packets with one or two
VLAN Headers. Packets with more than two VLAN Headers are allowed to pass, but only
the first two VLAN headers will not be compressed.
C.5 Multicast BPM Behavior
In BPM Mode, Multicast packets are forwarded in two directions:
• Outbound Path (CTOG-250 ► CDM-840): Multicast packets arriving at the CTOG-250 are
passed out the WAN to all CDM-840s using the “VCM Only MODCOD” option for the
matching QoS Group (based upon VLAN or Subnet).
• Return Link Path (CDM-840 ► CDD-880 ► CTOG-250): Multicast packets arriving into the
CDM-840 Traffic port are automatically passed out the CTOG-250’s Traffic port only.
Internet Control messages (such as OSPF, RIP, and BGP) that fall into the 224.0.0.0 -
224.0.1.255 address range are automatically passed out both the CTOG-250’s LAN and
WAN ports.
Figure C-6. Multicast Behavior in BPM Mode