Port mapping associates customer premises equipment (CPE) clients of a DSLAM with VLAN subinterfaces on the BRAS. The VLANs
include 802.1Q or queue-in-queue (Q-in-Q) hierarchical VLANs. Port mapping is configured in global configuration mode on the
BRAS by grouping CPE client IDs with a specific DSLAM neighbor.
There are two methods you can use to map ports: configure all VLAN subinterfaces first, and the ANCP neighbor mappings next.
Or, you can configure the mappings directly under the interface.
For example, the following commands configure port mapping for Q-in-Q VLAN subinterfaces:
ancp neighbor name
dslam-name
id
dslam-id
dot1q
outer-vlanid
second-dot1q
inner-vlanid
[interface
type number
] client-id
"
client-id
"
or
ancp neighbor name
dslam-name
id
dslam-id
dot1q
outer-vlanid
client-id
"
client-id
"
The client-id is a unique access-loop-circuit-id that the DSLAM sends to the BRAS for each unique port. The DSLAM sends this ID in the ANCP
Port Up event message. The access-loop-circuit-id uses a defined format consisting of an access node identifier and digital
subscriber line (DSL) information as mentioned below:
ATM/DSL
"
access-node-identifier
atm
slot/module/port
.
subinterface
:
vpi
.
vci
"
Ethernet/DSL
"
access-node-identifier
ethernet
slot
/
module
/
port
.
subinterface
[: vlan-id ]"
The BRAS sets the default state as Down, on all ports of the router, until the DSLAM sends a Port Up message.