Junos® OS Ethernet Interfaces Configuration ... - Juniper Networks

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OS 12.3 Ethernet Interfaces Configuration Guide
Table 8: Rewrite Operations on Untagged, Single-Tagged, and
Dual-Tagged Frames (continued)
Rewrite Operation
swap-swap
pop-pop
pop-swap
Untagged
No
No
No
Single-Tagged
No
No
No
Dual-Tagged
Yes
Yes
Yes
Number of Tags
The rewrite operations push and push-push can be valid in certain circumstances on
frames that are not tagged. For example, a single-tagged logical interface (interface 1)
and a dual-tagged logical interface (interface 2) have the following configurations:
Interface 1 [edit interfaces interface-name unit logical-unit-number]
input-vlan-map {
pop;
}
output-vlan-map {
push;
}
Interface 2 [edit interfaces interface-name unit logical-unit-number]
input-vlan-map {
pop-pop;
}
output-vlan-map {
push-push;
}
When a frame is received on the interface as a result of the input-vlan-map operation,
the frame is not tagged. As it goes out of the second interface, the output-vlan-map
operation push-push is applied to it. The resulting frame will be dual-tagged at the logical
interface output.
Depending on the VLAN rewrite operation, you configure the rewrite operation for the
interface in the input VLAN map, the output VLAN map, or in both the input VLAN map
and the output VLAN map. Table 9 on page 132 shows what rewrite operation combinations
you can configure. “None” means that no rewrite operation is specified for the VLAN map.
Table 9: Applying Rewrite Operations to VLAN Maps
132
Input VLAN Map
none
push
pop
Output VLAN Map
none
Yes
No
No
push
No
No
Yes
pop
No
Yes
No
swap
Yes
No
No
push-push
No
No
No
swap-push
No
No
No
swap-swap
Yes
No
No
0
– 2
– 1
pop-pop
No
No
No
swap-pop
No
No
No
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