User guide

Packet Over SONET Module Installation and User Guide 3-3
Basic PoS Module Configuration Information
PoS Port Configuration and Default VLAN Assignments
The ports on the PoS modules are identified by a port number that is a combination of
the slot number where the module is installed and the port number on the module. The
nomenclature for the port number is as follows:
slot:port
For example, you would refer to the four ports on an OC-3 PoS module installed in
slot 4 of the BlackDiamond 6800 series chassis by the port numbers 4:1, 4:2, 4:3, and 4:4.
For more information about port numbers and port configuration, see the
ExtremeWare Software User Guide.
Because the default Point-to-Point Protocol (PPP) network control protocol is the Bridge
Control Protocol (BCP), all PoS ports are initially enabled for bridging. By default, only
ports 1 and 3 on the OC-3 PoS modules are assigned to the default VLAN, while ports 2
and 4 are not assigned to a VLAN.
Because the first port pair on the OC-3 PoS modules (ports 1 and 2) and the second port
pair (ports 3 and 4) use a common link to the switch backplane, ports belonging to the
same port pair cannot be assigned to the same VLAN. The only exception to this rule is
when APS is defined and one of the two ports of a port pair is used as the working line
port, while the second port is used as the protection line port.
The port-pair restriction described above for the OC-3 PoS modules does not
apply to the OC-12 PoS module.
Default Configuration: Bridging Over PoS Ports
The default configuration of the OC-3 PoS module enables you to connect either port 1
or 3 (not both) of an OC-3 PoS module in a BlackDiamond 6800 series switch to either
port 1 or 3 of an OC-3 PoS module in a second BlackDiamond switch. In this
configuration, all ports reside in the default VLAN and traffic is bridged between all
ports in the VLAN. If you enable the Spanning Tree protocol, you can connect more
ports in parallel, but they will be blocked for traffic transmission. Loadsharing is not
supported over PoS links.
Configuration Commands for BCP
The bridged network example shown in Figure 3-1 does not require additional
configuration commands for BCP support, because the default SONET and PPP