Enterasys Networks Security Router X-PeditionTM - Manual (Page 123)

IP Routing Protocols
XSR User’s Guide 5-21
Figure 5-5 VLAN Ethernet to Fast/GigabitEthernet Topology
VLAN Processing: VLAN-enabled Ethernet to WAN Interfaces
In this scenario, shown in Figure 5-6 , the XSR does not insert a VLAN tag in Ethernet frames
because no VLAN is linked with the outgoing port (Serial 1).
Figure 5-6 VLAN Ethernet to WAN Interfaces Topology
VLAN Processing: WAN Interface to a VLAN-enabled Ethernet Interface
In this scenario, as shown in Figure 5-7 , a VLAN tag is inserted since a VLAN ID (1200) is
associated with the outgoing VLAN sub-interface (FastEthernet 1.1). The packet will be forwarded
to IP address 9.9.9.1 of the next-hop router. For traffic which did not enter the XSR from a VLAN
sub-interface, the priority bits are set to 0 (lowest level).
1
2
3
Incoming VLAN tagged frame
F1.1
VLAN 1200
IP 1.2.3.4/24
Ethernet VLAN Tag IP: 9.9.9.1
Ethernet IP: 9.9.9.1
Priority CFI VLAN: 1300
IP 3.2.3.4/24
F2
IP Routing Table
1.2.3.0/24 F1.1
3.3.2.0/24 F2
9.9.9.0/24 F2 (Static)
Outgoing Ethernet frame
Note: VLAN tags cannot be assigned to a WAN interface - they are relevant only for XSR
FastEthernet and GigabitEthernet interfaces.
1
2
3
Incoming VLAN tagged frame
F1.1
VLAN 1200
IP 1.2.3.4/24
Ethernet VLAN Tag IP: 9.9.9.1
PPP IP: 9.9.9.1
Priority CFI VLAN: 1200
IP 3.2.3.4/24
Serial 1
IP Routing Table
1.2.3.0/24 F1.1
3.3.2.0/24 Serial 1
9.9.9.0/24 Serial 1 (Static)
Outgoing Serial frame
PPP encapsulation