Extreme Networks ExtremeWare Command Reference Manual page 1338

T1, E1, and T3 WAN Commands
limitation with RFC 1638-based BCP is that 802.1Q tags are not supported. So Legacy BCP cannot
support multiple VLANs or preserve 802.1p priority across the PPP link. Both types of BCP can operate
over single and multilink PPP.
When BCP is negotiated over a link, RFC 2878 BCP is initially proposed. If the peer only supports
Legacy BCP (RFC 1638), then the link is made using Legacy BCP. Since the WAN module ports are
always configured as tagged ports, the VLAN tag is removed in the egress direction and inserted in the
egress direction when BCP is operating in Legacy mode.
There is no Legacy BCP specific configuration, and the display for the command is
show ppp info
identical for BCP and Legacy BCP. To determine if the link is using Legacy BCP, use the following
command:
show log warning
and look for the message:
BCP: Legacy BCP UP;Only a single VLAN over BCP is supported
Example
The following command example configures IPCP on a PPP port, and applies to a WAN module
installed in slot 1 of an Alpine switch:
config ppp ipcp on port 1:4
History
This command was first available in ExtremeWare v6.1.5w2.01WAN technology release.
This command was subsequently incorporated into ExtremeWare 7.0.0.
Platform Availability
This command is available on the Alpine 3800 series platform, when a WAN module is installed. A
similar command is available on the BlackDiamond switch.
1338 ExtremeWare Software 7.0.0 Command Reference Guide