Juniper JUNOSE 11.2.X BGP AND MPLS Configuration Manual page 594

JunosE 11.2.x BGP and MPLS Configuration Guide
558
Two customer premise equipment (CPE)-facing interfaces send a packet each to the
local CE device, CE1. The Ethernet packet is tagged with both an S-VLAN ID and a C-VLAN
ID from CPE1, while the packet from CPE2 contains only the S-VLAN ID. These packets
are forwarded to the local PE-router, PE1. In this case, two pseudowires are required for
the two conditions. Configuring the C-VLAN ID as 0 by using the anyUntagged keyword
in the svlan id svlanIDValue command enables both double-tagged and single-tagged
traffic that matches the S-VLAN ID to pass through the S-VLAN subinterface. Using such
a configuration, you need to create only one pseudowire and only one S-VLAN subinterface
on PE routers.
If an S-VLAN subinterface is configured with Ethertype as 0x8100 and C-VLAN ID as any,
a VLAN subinterface for the same ID shall cannot be configured, and vice-versa. For
example, you cannot configure the following two commands simultaneously:
host1(config-if)#svlan id X any
host1(config-if)#svlan ethertype 8100
and
host1(config-if)#vlan id X
If you configure such a setting, the set of commands that is configured first takes
precedence. Consider the following two cases with this configuration:
Case 1: Assume that svlan id X any 8100 is configured on the subinterface. In this case,
all packets with the outer tag as X and Ethertype as 8100 are matched to the
sub-interface.
Case 2: Assume that vlan id X is configured on the subinterface. In this case, only
single-tagged packets with VLAN ID X and Ethertype of 8100 are matched to this
subinterface. For VLAN ID of 0, the untagged traffic and the priority tagged traffic are
matched the subinterface. This behavior is how it works in existing implementation.
If the S-VLAN subinterface is configured with any value other than an Ethertype 8100,
both S-VLAN and VLAN interfaces for the same ID can be configured together as listed
earlier. In such cases, the packets are expected to arrive with an S-VLAN ID other than
0x8100 and the C-VLAN Ethertype as 0x8100, which helps to uniquely identify the
subinterface for all the following traffic patterns:
Untagged
C-VLAN tag only
S-VLAN tag only
Both S-VLAN and C-VLAN tagged
The following set of commands generates in appropriate error messages when you
attempt to configure them on a VLAN major interface:
host1(config-if)#interface fastEthernet 1/1.1
host1(config-if)#svlan id X anyUntagged
host1(config-if)#svlan Ethertype 0x8100
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