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- Related Topics
- Example: Configuring a Virtual Chassis with a Master and Backup in a Single Wiring Closet
- Example: Expanding a Virtual Chassis in a Single Wiring Closet
- Example: Setting Up a Multimember Virtual Chassis Access Switch with a Default Configuration
- Example: Configuring a Virtual Chassis with a Preprovisioned Configuration File
- Setting an Uplink Port as a Virtual Chassis Port (CLI Procedure)
Example: Configuring a Virtual Chassis Interconnected Across Multiple Wiring Closets
A virtual chassis is a very adaptable access switch solution. You can install member switches in different wiring closets, interconnecting the member switches by cabling and configuring uplink ports as virtual chassis ports (VCPs).
This example describes how to configure a virtual chassis access switch interconnected across wiring closets:
Requirements
This example uses the following hardware and software components:
- JUNOS Release 9.0 or later software for EX-series switches
- Two EX 4200-48P switches
- Two EX 4200-24T switches
- Four EX-UM-2XFP uplink modules
Before you interconnect the members of the virtual chassis across wiring closets, be sure you have:
- Installed an EX-UM-2XFP uplink module in the member switches that will be interconnected across wiring closets. See Installing an Uplink Module in an EX-series Switch.
- Powered on, connected and run the EZ Setup program on SWA-0. Follow the prompts to specify the host name and other identification, time zone, and network properties. See Connecting and Configuring the EX-series Switch (CLI Procedure) for details. SWA-0 is going to be configured in the example to function as the master of the virtual chassis. Thus, the properties that you specified for SWA-0 apply to the entire virtual chassis, including all the member switches that you later interconnect with the master.
- Configured SWA-0 with the virtual management Ethernet
(VME) for remote, out-of-band management of the virtual chassis, if
desired.
[edit]
user@SWA-0# set interfaces vme unit 0 family inet /ip-address/mask/ - Interconnected SWA-0 and SWA-1 (the two member switches in wiring closet A) using the dedicated VCPs on the rear panel. SWA-1 should not be powered on at this time.
- Interconnected SWA-2 and SWA-3 (the two member switches in wiring closet B) using the dedicated VCPs on the rear panel. SWA-2 and SWA-3 should not be powered on at this time.
 |
Note: To set an uplink as a VCP interface, it must be one of the 10-Gigabit Ethernet uplinks (EX-UM-2XFP uplink module). When an uplink port is set as a VCP interface, it cannot be used for any other purpose. The EX-UM-2XP uplink module has two ports. You can set one port as a VCP interface and configure the other port in trunk mode as an uplink to a distribution switch. |
Overview and Topology
In this example, four EX 4200 switches will be interconnected as a virtual chassis. Two switches (SWA-0 and SWA-1) are located in wiring closet A and two switches (SWA-2 and SWA-3) are located at the other end of the floor in wiring closet B.
For easier monitoring and manageability, we want to interconnect all four switches as members of a virtual chassis. Prior to configuring the virtual chassis, we installed uplink modules in each of the member switches. We are going to interconnect the member switches across wiring closets setting the 10-Gigabit Ethernet uplink ports as VCP interfaces. In this example, uplink modules are installed in all four members so that there are redundant VCP connections across the wiring closets. If you want to expand this configuration to include more members within these wiring closets, you do not need to add any more uplink modules. Simply use the dedicated VCPs on the rear panel. The redundancy of uplink VCPs provided in this example is sufficient.
First, we will complete the virtual chassis configuration of the member switches in wiring closet A.
We have decided that SWA-0 will function as the master, so we set its mastership priority value to the highest possible value (255).
The switches (SWA-0 and SWA-1) in wiring closet A have been interconnected using the dedicated virtual chassis ports (VCPs) . The interfaces for the rear panel, dedicated VCPs are operational by default. They do not need to be configured.
However, the rear-panel virtual chassis cables that interconnect the VCPs of member switches within a single wiring closet are not long enough to connect member switches across wiring closets. Instead, you can use the fiber cable connections in the uplink modules to interconnect the member switches in wiring closet A to the member switch in wiring closet B. For redundancy, this example connects uplink ports from the two member switches in wiring closet A to the two member switches in wiring closet B.
After specifying the highest mastership priority value (255) for SWA-0, we power on SWA-1. Because SWA-0 and SWA-1 are interconnected with the dedicated VCPs, the master detects that SWA-1 is a member of its virtual chassis and assigns a member ID. We can now set the VCP uplinks for both SWA-0 and SWA-1 through the master in preparation for interconnecting them with the member switches in wiring closet B.
However, in order for the master to recognize the existence of SWA-2, you must first set one of the SWA-2 uplinks as a VCP. You cannot set the SWA-2 uplink through the master of the virtual chassis, because SWA-2 is not yet interconnected as a member switch.
We will power on and configure SWA-2 prior to powering on SWA-3.
When you power on SWA-2, its member ID is 0, its default mastership priority is 128, and it is functioning in the master role.
You can configure SWA-2 without running EZ Setup by directly connecting to the console port. If you wish, you can run EZ Setup and specify identification parameters. Later, when you interconnect SWA-2 with the master of the virtual chassis, the master overwrites any conflicting parameters.
We want to use SWA-2 as the backup of the virtual chassis. If a problem occurs in wiring closet A, SWA-2 would take control of the virtual chassis and maintain the network connections. We configure the same mastership priority value for SWA-2 (255) that we configured for the master. Because SWA-0 has already been powered on prior to SWA-2, it has additional prioritization properties that allow it to retain mastership of the virtual chassis. See Understanding How the Master in a Virtual Chassis Is Elected for additional information about the election of the master. We recommend setting identical mastership priority values for the master and backup members for high availability and smooth transition of mastership in case the original master becomes unavailable. (It prevents the previous master from pre-empting the master role from the new master when the previous master comes back online.)
After SWA-2 has been configured and its uplink port has been set as a VCP interface, interconnect its VCP uplink port with the VCP uplink of SWA-0 in wiring closet A. SWA-2 reboots and joins the virtual chassis as member 2 and as backup of the expanded virtual chassis.
Now, power on SWA-3. Because SWA-3 is interconnected with SWA-2 using the dedicated VCPs on the rear panel, the master detects that SWA-3 is part of the expanded virtual chassis and assigns it member id 3. For redundancy, configure a VCP uplink on member 3 through the master and interconnect this uplink with the VCP uplink of SWA-1 in wiring closet A.
The topology for this example consists of:
- Two EX 4200-48P switches
- Two EX 4200-24T switches
- Four EX-UM-2XFP uplink modules.
Table 1 shows the virtual chassis configuration settings for a virtual chassis composed of member switches in different wiring closets.
Table 1: Components of a Virtual Chassis Interconnected Across Multiple Wiring Closets
Figure 1 shows the different types of interconnections used for this virtual chassis configuration. The rear view shows that the member switches within each wiring closet are interconnected to each other using the dedicated VCPs. The front view shows that the uplink ports that have been set as VCP interfaces and interconnected across the wiring closets. The uplink ports that are not used as VCPs can be configured as trunk ports to connect to a distribution switch.
Figure 1: A Virtual Chassis Interconnected Across Wiring Closets
Configuration
To configure the virtual chassis across multiple wiring closets, perform these tasks:
|
Note: We recommend that you use the commit synchronize command to save any configuration changes that you make to a multimember virtual chassis. |
CLI Quick Configuration
To quickly configure a virtual chassis across multiple wiring closets, configure a master in one closet and a backup in the other by copying the following commands into the specified terminal windows (SWA-0 and SWA-2):
[edit]
user@SWA-0#set
virtual-chassis member 0 mastership-priority 255
[edit]
user@SWA-2#set
virtual-chassis member 0 mastership-priority 255
|
Note: At this point, SWA-2 is a standalone switch, so its member ID is 0. |
Step-by-Step Procedure
To configure a virtual chassis across multiple wiring closets:
- Configure the mastership priority of SWA-0 (member 0) to be the highest possible value (255), thereby
ensuring that it functions as the master of the expanded virtual chassis.
[edit virtual-chassis]
user@SWA-0#set member 0 mastership-priority 255 - Prepare the members in wiring closet A for interconnecting
with the member switches in wiring closet B by setting uplink VCPs
for member 0 and member 1:
user@SWA-0> request virtual-chassis vc-port set pic-slot 1 port 0
user@SWA-0> request virtual-chassis vc-port set pic-slot 1 port 0 member 1- For redundancy, this example configures an uplink VCP in both SWA-0 and SWA-1.
- This example omits the specification of the member member-id option in configuring the uplink for SWA-0. The command applies by default to the switch where it is executed.
- Prepare the potential member switch (SWA-2) in
wiring closet B for interconnecting with the virtual chassis by configuring
its mastership priority to be the highest possible value (255). Its
member ID is currently 0, because it is not yet interconnected with
the other members of the virtual chassis. It is operating as a standalone
switch. Its member ID will change when it is interconnected.
[edit virtual-chassis]
user@SWA-2# set member 0 mastership-priority 255
Note: SWA-2 is configured with the same mastership priority value that we configured for SWA-0. However, the longer uptime of SWA-0 ensures that it functions as the master and that SWA-2 functions as the backup.
- Specify one uplink port in SWA-2 as a VCP interface.
Its member ID is 0, because it is not yet interconnected with the
other members of the virtual chassis. Its member ID will change when
it is interconnected with the virtual chassis.
Note: The setting of the VCP interface remains intact when SWA-2 reboots and joins the virtual chassis as member 2.
user@SWA-2>request virtual-chassis vc-port set pic-slot 1 port 0
This example omits the specification of the member member-id option. The command applies by default to the switch where it is executed.
- After you have set the uplink VCP in SWA-2, you should physically interconnect SWA-0 and SWA-2 across wiring closets using their uplink VCPs. Although SWA-0 and SWA-2 have the same mastership priority value (255), SWA-0 was powered on first and thus has longer uptime. This results in SWA-0 retaining mastership while SWA-2 reboots and joins the now expanded virtual chassis as a backup with member ID 2.
- Power on SWA-3, which is interconnected with SWA-2
using the dedicated VCPs on the rear panel. It joins the expanded
virtual chassis as member 3.
Note: We have assumed that the member ID assigned to SWA-3 is 3, because it was powered on in that sequence.
- Since SWA-3 is now interconnected as a member of
the virtual chassis, you can specify a redundant VCP uplink on SWA-3
through the master of the virtual chassis.
user@SWA-0> request virtual-chassis vc-port set pic-slot 1 port 0 member 3 - After you have configured the uplink VCP of SWA-3, you should physically interconnect SWA-3 and SWA-1 across wiring closets using their uplink VCPs. Both SWA-1 and SWA-3 have the default mastership priority value (128) and function in a linecard role.
Configuration Results
Display the results of the configuration on SWA-0:
- [edit]
- user@switch# show
- virtual-chassis {
-
- member 0 {
- mastership-priority 255;
- }
-
- member 1 {
- mastership-priority 128;
- }
-
- member 2 {
- mastership-priority 255;
- }
-
- member 3 {
- mastership-priority 128;
- }
-
- member 4 {
- mastership-priority 128;
- }
-
- member 5 {
- mastership-priority 128;
- }
-
- member 6 {
- mastership-priority 128;
- }
-
- member 7 {
- mastership-priority 128;
- }
-
- member 8 {
- mastership-priority 128;
- }
-
- member 9 {
- mastership-priority 128;
- }
- }
Verification
To confirm that the configuration is working properly, perform these tasks:
- Verifying the Member IDs and Roles of the Member Switches
- Verifying That the Dedicated VCPs and Uplink VCPs Are Operational
Verifying the Member IDs and Roles of the Member Switches
Purpose
Verify that all the interconnected member switches are included within the virtual chassis and that their roles are assigned appropriately.
Action
Display the members of the virtual chassis:
user@SWA-0> show virtual-chassis status
Virtual Chassis ID: 0000.e255.00e0
Mastership Neighbor List
Member ID Status Serial No Model Priority Role ID Interface
0 (FPC 0) Prsnt abc123 ex4200-48p 255 Master* 1 vcp-0 1 vcp-1
2 1/0
1 (FPC 1) Prsnt def456 ex4200-24t 128 Linecard 0 vcp-0
0 vcp-1
3 1/0
2 (FPC 2) Prsnt ghi789 ex4200-48p 255 Backup 3 vcp-0 3 vcp-1
0 1/0
3 (FPC 3) Prsnt jkl012 ex4200-24t 128 Linecard 2 vcp-0
2 vcp-1
1 1/0
What it Means
The show virtual-chassis status command lists the member switches interconnected as a virtual chassis with the member IDs that have been assigned by the master, the mastership priority values, and the roles. It also displays the neighbor members with which each member is interconnected.
Verifying That the Dedicated VCPs and Uplink VCPs Are Operational
Purpose
Verify that the dedicated VCPs interconnecting the member switches in wiring closet A and the uplink VCPs interconnecting the member switches between wiring closets are operational.
Action
Display the virtual chassis interfaces:
user@SWA-0> show virtual-chassis vc-port all-members
fpc0: -------------------------------------------------------------------------- Interface Type Status or PIC / Port vcp-0 Dedicated Up vcp-1 Dedicated Up 1/0 Configured Up fpc1: -------------------------------------------------------------------------- Interface Type Status or PIC / Port vcp-0 Dedicated Up vcp-1 Dedicated Up 1/0 Configured Up fpc2: -------------------------------------------------------------------------- Interface Type Status or PIC / Port vcp-0 Dedicated Up vcp-1 Dedicated Up 1/0 Configured Up fpc3: -------------------------------------------------------------------------- Interface Type Status or PIC / Port vcp-0 Dedicated Up vcp-1 Dedicated Up 1/0 Configured Up
What it Means
The dedicated VCPs are displayed as vcp-0 and vcp-1. The uplinks configured as VCPs are displayed as 1/0. The fpc number is the same as the member ID.
Troubleshooting
To troubleshoot a virtual chassis that is interconnected across wiring closets, perform these tasks:
Problem
A VCP interface shows a status of down.
Solution
- Check the cable to make sure that it is properly and securely connected to the ports.
- If the VCP is an uplink port, make sure that the uplink module is model EX-UM-2XFP.
- If the VCP is an uplink port, make sure that the uplink port has been explicitly set as a VCP.
- If the VCP is an uplink port, make sure that you have specified the options (pic-slot, port-number, member-id) correctly.