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This chapter describes how to configure Fiber Distributed Data Interface (FDDI) IEEE 802.10 VLAN trunks.
This chapter consists of these sections:
You can extend VLANs across an FDDI backbone by multiplexing switched packets over a FDDI/CDDI interface using the 802.10 protocol. Catalyst 5000 family FDDI/CDDI interface links can operate as inter-switch trunks that provide broadcast control between configured VLANs. The 802.10 protocol encapsulates frames with a VLAN identifier and packet data according to the IEEE 802.10 specification. FDDI/CDDI interfaces that support 802.10 make selective forwarding decisions within a network domain based upon the VLAN identifier.
The VLAN identifier is a user-configurable four-byte Security Association Identifier (SAID). The SAID identifies traffic as belonging to a particular VLAN. The SAID also determines to which VLAN each packet is switched.
Figure 39-1 shows an example FDDI trunk configuration. In this example, the SAID ensures that packets destined for a particular VLAN are received on that VLAN after they are transmitted across the FDDI trunks.
FDDI/CDDI modules integrate switched Ethernet and Fast Ethernet LANs into the FDDI network. To map an 802.10 FDDI VLAN to an Ethernet VLAN, you must map the 802.10 VLAN SAID to an Ethernet VLAN by mapping an Ethernet VLAN to an FDDI VLAN and assigning a SAID value to the FDDI VLAN.
If an FDDI/CDDI module receives a packet containing a VLAN SAID that maps to a locally supported Ethernet VLAN on the Catalyst 5000 family switch, the FDDI/CDDI module translates the packet into Ethernet format and forwards it across the switch backplane to the Ethernet module. FDDI/CDDI modules filter the packets they receive from reaching the backplane if the VLAN SAIDs in the packets do not map to a locally supported VLAN.
Figure 39-2 illustrates the configuration for forwarding a packet from the Ethernet module port 1 in slot 2 to the FDDI module port 1 in slot 5. For this example, you would specify the translation of Ethernet VLAN 2 to FDDI VLAN 22. FDDI VLAN 22 is translated automatically to Ethernet VLAN 2. The VLAN SAID must be identical on both FDDI modules. Because 802.10 FDDI/CDDI interface links can operate as inter-switch trunks, you can configure multiple VLAN translations over a link.
FDDI/CDDI modules also support one native (nontrunk) VLAN, which handles all non-802.10 encapsulated FDDI traffic. You do not need to configure a translation number for the native VLAN because packets that are forwarded to the native VLAN do not contain VLAN identifiers. To map an Ethernet VLAN to an FDDI native VLAN, you must configure the FDDI port to be on the Ethernet VLAN. To do this, configure the Ethernet VLAN with the module number and port number of the FDDI-native VLAN.
Table 39-1 shows the FDDI/CDDI default configuration.
| Feature | Default Value |
|---|---|
Native VLAN | VLAN 1 |
Ethernet-FDDI mapping | None |
Trunking | Off |
Allowed VLAN range | VLANs 1-1005 |
These recommendations apply to setting up an FDDI 802.10 configuration:
To set up an FDDI 802.10 VLAN trunk configuration, perform this task in privileged mode:
| Task | Command |
|---|---|
Step 1 Create an Ethernet VLAN. | set vlan vlan_num |
Step 2 Create an FDDI VLAN. | set vlan vlan_num type fddi |
Step 3 Map the Ethernet VLAN to the FDDI VLAN. | set vlan ether_vlan translation fddi_vlan |
Step 4 Turn trunking on for the FDDI port. | set trunk mod_num/port_num on |
Step 5 Repeat Steps 1-3 for additional VLANs you want carried over the trunk link. |
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Step 6 Verify the trunk configuration. | show vlan trunk |
Figure 39-3 shows two Catalyst 5000 family switches in an FDDI 802.10 VLAN configuration.
The following prerequisites apply to the FDDI 802.10 configuration example shown in Figure 39-3:
After completing the tasks in "Configuring VLANs," complete this task in privileged mode to set up the FDDI 802.10 VLAN configuration for VLAN 33:
| Task | Command |
|---|---|
Step 1 Provide a VLAN number and activate a VLAN in the management domain. | set vlan 33 |
Step 2 Create a VLAN with the type FDDI. | set vlan 33 type fddi |
Step 3 Map the Ethernet VLAN translation to an FDDI VLAN. | set vlan 333 translation 33 or set vlan 33 translation 333 |
Step 4 Turn trunking on for the FDDI port. | set trunk 1/1 on |
After entering the set vlan 33 command, you see this display:
Console> (enable) set vlan 33 VTP: vlan addition successful
This command creates a VLAN but does not assign it to a port. VTP advertises the VLAN to all available trunks of all types (such as Ethernet or FDDI) that are set to on, for all switches in the same management domain.
After entering the set vlan vlan_num type fddi command, you see this display:
Console> (enable) set vlan 333 type fddi (said 338) VTP: vlan addition successful
After entering the set vlan vlan_num translation vlan_num command or the set vlan vlan_num translation vlan_num command, you see this display:
Console> (enable) set vlan 33 translation 333 VTP: vlan modification successful
After entering the set trunk 1/1 on command, you see this display:
Console> (enable) set trunk 1/1 on Port 1/1 mode set to on. Console> (enable)
To verify that the VLAN configuration is correct, including the mapping between Ethernet, FDDI, and Token Ring, enter the show vlan command and the show trunk command. After entering the show vlan command, you see this display:
Console> (enable) show vlan VLAN NameType Status Mod/Ports ---- ------------------------------- --------- ---------------- 1 default enetactive1/1 2/3-4,2/7-12,2/14-16,2/18-24 11 VLAN0011 enet active 2/1-2 22 VLAN0022 enet active 2/5-6 33 VLAN0033 enet active 2/13,2/17 111 VLAN0111 fddi active 222 VLAN0222 fddi active 333 VLAN0333 fddi active 1002 fddi-default fddi active 1003 token-ring-default tring active 1004 fddinet-default fdnet active 1005 trnet-default trnet active VLAN SAIDMTU RingNo BridgeNo StpNo Parent Trans1 Trans2 ---- ---------- ----- ------ -------- ----- ------ ------ ------ 1 1 1500 0 0 0 0 0 0 11 11 1500 0 0 0 0 111 0 22 22 1500 0 0 0 0 222 0 33 100033 1500 0 0 0 0 333 0 111 111 1500 0 0 0 0 11 0 222 222 1500 0 0 0 0 22 0 333 338 1500 0 0 0 0 33 0 1002 1002 1500 0 0 0 0 0 0 1003 1003 1500 0 0 0 0 0 0 1004 1004 1500 0 0 0 0 0 0 1005 1005 1500 0 0 0 0 0 0 Console> (enable)
Posted: Fri Oct 1 13:28:00 PDT 1999
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