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Classic Token Ring Bridged Network Migration

Classic Token Ring Bridged Network Migration

The Catalyst 3900 Token Ring switch and Catalyst 5000 Token Ring switch module can be used to collapse network backbones and floor rings in classic Token Ring environments with redundantly placed source-route bridges. The use of a Catalyst Token Ring switch in this scenario improves network performance by eliminating the need for multiple bridges and by allowing the direct attachment of high-utilization devices, such as servers, front-end processors, and routers.

This section provides an example of using Catalyst Token Ring switches to replace multiple bridges in a classic Token Ring network.

Initial Network Configuration

In your company, you have two backbone rings that service five floor rings. You have a server, router, and front-end processor attached to each of the backbone rings. Because the number of users is growing and there is an increased need to access the devices that are attached to the backbone rings, you need to improve the performance of your network. You have decided to replace one ring with a Catalyst 3900 and one with a Catalyst 5000 with a Token Ring switching module.

Figure 8-1 illustrates the initial network configuration.


Figure 8-1: Initial Network Configuration

Configuration Steps

To configure your collapsed backbone network, on each switch you will need to configure a new bridge (or TrBRF) as you cannot add TrCRFs to the default TrBRF, a ring (or TrCRF) for each floor, as well as a TrCRF that will contain the high-utilization devices.


Note For more information about Token Ring VLANs, see the "Token Ring VLANs and Related Protocols" chapter.

Configuring the Catalyst 3900

On the Catalyst 3900, you must configure a new bridge (TrBRF), six new rings (TrCRFs), and the Spanning-Tree Protocol.


Note You must assign the ports to the TrCRFs before you can configure spanning-tree parameters for the TrCRFs.

Defining the Bridges

To define a bridge (TrBRF), complete the following steps:


Step 1   On the Catalyst 3900 Main Menu, select Configuration. The Configuration panel is displayed.

Step 2   On the Configuration panel, select VLAN and VTP Configuration. The VLAN and VTP Configuration panel is displayed.

Step 3   On the VLAN and VTP Configuration panel, select VTP VLAN Configuration. The VTP VLAN Configuration panel is displayed.

Step 4   On the VTP VLAN Configuration panel, select Add.

Step 5   At the prompt, enter a VLAN ID of 100 .

Step 6   At the prompt, select TrBRF. The VLAN Parameter Configuration for TrBRF panel is displayed.

Step 7   On the VLAN Parameter Configuration for TrBRF panel, specify:

See Figure 8-2.


Figure 8-2: VLAN Parameter Configuration for TrBRF Panel

Step 8   Select Return to save your changes.

Defining the Rings

To define the rings (TrCRFs) for the first floor, complete the following steps:


Step 1   On the VTP VLAN Configuration panel, select Add.

Step 2   At the prompt, enter a VLAN ID of 101.

Step 3   At the prompt, select TrCRF. The VLAN Parameter Configuration for TrCRF panel is displayed.

Step 4   On the VLAN Parameter Configuration for TrCRF panel, specify:

See Figure 8-3.


Figure 8-3: VLAN Parameter Configuration for TrCRF Panel

Step 5   Select Return to save your changes.

To define the TrCRFs for the remaining floors, repeat Step 1 through Step 5 and use the following values:

To define the TrCRF for the high-utilization devices, repeat Step 1 through Step 5 and use the following values:

Figure 8-4 shows the resulting VTP VLAN Configuration panel.


Figure 8-4: VTP VLAN Configuration Panel

Assigning Ports to the Rings

Next, you must assign the ports to the appropriate TrCRFs. On the Catalyst 3900, complete the following steps:


Step 1   On the VLAN and VTP Configuration panel, select Local VLAN Port Configuration. The Local VLAN Port Configuration panel is displayed.

Step 2   On the Local VLAN Port Configuration panel, select Change.

Step 3   At the prompt enter port number 1.

Step 4   Select Floor 1 from the list of possible TrCRFs. To select the TrCRF, use your cursor movement keys to highlight the desired TrCRF, press the space bar to select it, and press Enter to implement your change. See Figure 8-5.


Figure 8-5: Local VLAN Port Configuration Panel

Step 5   Repeat Step 2 through Step 4 to assign the ports to the appropriate TrCRFs as follows:

Ports TrCRF

2

Floor 1

3, 4

Floor 2

5, 6

Floor 3

7, 8

Floor 4

9, 10

Floor 5

11, 12, 13

Server Ring 1

Step 6   Select Return to save your changes.

Configuring the Spanning-Tree Protocol

If you install an external bridge to create a backup path between rings 1 and 4, you introduce possible loops into your network. You can use the Spanning-Tree Protocols to prevent these loops. By default, no Spanning-Tree Protocol is run at the bridge (TrBRF) or the ring (TrCRF) level, therefore, you must configure the Spanning-Tree Protocol.

To configure the Spanning-Tree Protocol for the TrBRF, complete the following steps:


Step 1   On the Catalyst 3900 Main Menu, select Configuration. The Configuration panel is displayed.

Step 2   On the Configuration panel, select Spanning Tree and select BRF100. The Spanning Tree for TrBRF panel is displayed.

Step 3   On the Spanning Tree for TrBRF panel, set the STP Participation to IBM. See Figure 8-6.


Figure 8-6: Spanning Tree for TrBRF Panel

To configure the Spanning-Tree Protocol for the TrCRF, do the following:


Step 1   While still on the Spanning Tree for TrBRF panel, select TrCRF & Port Spanning Tree Parameters and select Floor 1. The Spanning Tree for TrCRF panel is displayed.

Step 2   On the Spanning Tree for TrCRF panel, set the STP Participation to IEEE. See Figure 8-7.


Figure 8-7: Spanning Tree for TrCRF Panel

Step 3   Select Return.

Step 4   Repeat Steps 1-3 for Floor 2, Floor 3, Floor 4, Floor 5, and Server Ring 1.

Step 5   Select Return again.

Configuring the Catalyst 5000

On the Catalyst 5000, you must configure a new bridge (TrBRF), six new rings (TrCRFs), and the Spanning-Tree Protocol. You have inserted the Token Ring module into slot 2 of the Catalyst 5000.

Defining the Bridge

To define the bridge (TrBRF), complete the following steps:


Step 1   At the Catalyst 5000 command prompt, enter enable.

Step 2   At the enable prompt, enter set vlan 200 name brf200 type trbrf bridge 2.

Step 3   To verify the configuration of the new VLAN, enter show vlan.

The output, as shown in Figure 8-8, indicates that brf200 has been added but that it does not have any TrCRFs assigned to it yet.


Figure 8-8: Output for Show VLAN Command VLAN Name Status Mod/Ports, Vlans ---- -------------------------------- --------- ---------------------------- 1 default active 1/1-2 200 brf200                           active 1002 fddi-default active 1003 trcrf-default active 2/1-16 1004 fddinet-default active 1005 trbrf-default active 1003

Defining the Rings

To define the ring (TrCRF) for the first floor, complete the following steps:


Step 1   At the enable prompt, enter:

set vlan 201 name Floor_1 type trcrf ring 1 parent 200 mode srb

Step 2   To verify the configuration of the new VLAN, enter show vlan.

The output, as shown in Figure 8-9, indicates that FLoor_1 has been added but that it does not have any ports assigned to it yet. It also shows that brf200 is the parent of the VLAN with the ID of 201.


Figure 8-9: Output of Show VLAN Command VLAN Name Status Mod/Ports, Vlans ---- -------------------------------- --------- ---------------------------- 1 default active 1/1-2 200 brf200                           active 201 201  Floor_1                          active 1002 fddi-default active 1003 trcrf-default active 3/1-16 1004 fddinet-default active 1005 trbrf-default active 1003 VLAN Type SAID MTU Parent RingNo BrdgNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ ------ ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 200 trbrf 100200 4472 - - 0x2    ibm - 0 0 201  trcrf 100201     4472 100 0x01   - - srb 0 0 1002 fddi 101002 1500 - 0x0 - - - 0 0 1003 trcrf 101003 4472 1005 0xccc - - srb 0 0 1004 fdnet 101004 1500 - - 0x0 ieee - 0 0 1005 trbrf 101005 4472 - - 0xf ibm - 0 0

To define the TrCRFs for the remaining floors, enter the set vlan commands as follows:

set vlan 202 name Floor_2 type trcrf ring 2 parent 200 mode srb set vlan 203 name Floor_3 type trcrf ring 3 parent 200 mode srb set vlan 204 name Floor_4 type trcrf ring 4 parent 200 mode srb set vlan 205 name Floor_5 type trcrf ring 5 parent 200 mode srb

To define the TrCRF for the server ring, enter the set vlan commands as follows:

set vlan 207 name Server_Ring_2 type trcrf ring 7 parent 200 mode srb

The output, as shown in Figure 8-10, indicates that the TrCRFs have been added but that there are no ports assigned to them yet. It also shows that brf200 is the parent of the new TrCRFs.


Figure 8-10: Output of Show VLAN Command VLAN Name Status Mod/Ports, Vlans ---- -------------------------------- --------- ---------------------------- 1 default active 1/1-2 200 brf200                           active    201, 202, 203, 204, 205, 207 201  Floor_1                          active 202  Floor_2                          active 203  Floor_3                          active 204  Floor_4                          active 205  Floor_5                          active 207  Server_Ring_2                    active 1002 fddi-default active 1003 trcrf-default active 2/1-16 1004 fddinet-default active 1005 trbrf-default active 1003 VLAN Type SAID MTU Parent RingNo BrdgNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ ------ ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 200 trbrf 100200 4472 - - 0x2    ibm - 0 0 201  trcrf 100201     4472 200 0x01   - - srb      0 0 202  trcrf 100202     4472 200 0x02   - - srb      0 0 203  trcrf 100203     4472 200 0x03   - - srb      0 0 204  trcrf 100204     4472 200 0x04   - - srb      0 0 205  trcrf 100205     4472 200 0x05   - - srb      0 0 207  trcrf 100207     4472 200 0x07   - - srb      0 0 1002 fddi 101002 1500 - 0x0 - - - 0 0 1003 trcrf 101003 4472 1005 0xccc - - srb 0 0 1004 fdnet 101004 1500 - - 0x0 ieee - 0 0 1005 trbrf 101005 4472 - - 0xf ibm - 0 0

Assigning Ports to the Rings

To assign the ports to the rings (TrCRFs), enter the set vlan command at the enable prompt as follows:

set vlan 201 23/1-2 set vlan 202 2/3-4 set vlan 203 2/5-6 set vlan 204 2/7-8 set vlan 205 2/9-10 set vlan 207 2/11-13

The output, shown in Figure 8-11, shows that two ports on the module are assigned to each of the five TrCRFs that represent each floor and that three ports are assigned to Server_Ring_2.


Figure 8-11: Output of Show VLAN Command VLAN Name Status Mod/Ports, Vlans ---- -------------------------------- --------- ---------------------------- 1 default active 1/1-2 200 brf200                           active    201, 202, 203, 204, 205, 207 201  Floor_1                          active    2/1-2 202  Floor_2                          active    2/3-4 203  Floor_3                          active    2/5-6 204  Floor_4                          active    2/7-8 205  Floor_5                          active    2/9-10 207  Server_Ring_2                    active    2/11-13 1002 fddi-default active 1003 trcrf-default active 2/14-16 1004 fddinet-default active 1005 trbrf-default active 1003

Configuring the Spanning-Tree Protocol

By default, the TrBRF runs the IBM Spanning-Tree Protocol. The Spanning-Tree Protocol run on the TrCRFs is determined by the specified bridging mode. TrCRFs with a bridge mode of SRB will run the IEEE Spanning-Tree Protocol and TrCRFs with a bridge mode of SRT will run the Cisco Spanning-Tree Protocol.

Cabling the Network

Using the appropriate cabling, attach ports 1 and 2 of the Catalyst 3900 to the existing ring on floor 1. Repeat this for each of the floors. Then attach port 11 to the router, port 12 to the server, and port 13 to the front-end processor. Do the same for the ports on the Catalyst 5000.

Resulting Network Configuration

You now have a faster, more efficient network that includes less hardware to maintain. (See Figure 8-12.)


Figure 8-12: Resulting Network

Tips

To further improve performance, if you have 16 Mbps connections and the network interface card (NIC) supports full-duplex, you can configure the ports connected to the servers to operate in FDX mode. To configure FDX:


Step 1   Select Port Configuration on the Configuration panel.

Step 2   Specify the port to which the high-utilization device is attached. In this scenario, that would be ports 11, 12, and 13.

Step 3   On the Port Configuration panel, move to the Operation Mode and select a mode of FDX port.

Step 4   Select Return.


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Posted: Wed Oct 2 03:37:57 PDT 2002
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