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This configuration provides redundant network access to the chassis, protecting against link failure or management

module failure. You can cable the redundant connections to the same top of rack switch or to two redundant switches,

just be sure to configure both connections the same and have them on the same network and VLAN.

As mentioned above, there is no need to prefer either GB 1 or GB 2 for these connections.

Cabling an Individual Chassis

With the automatic uplink detection and network loop prevention, it is possible to connect multiple chassis one to the

other with cables to save port usage in the data center switches and still access each chassis over the network. When

multiple chassis are cabled in this manner it is known as a “stack”.

Note: While the automatic uplink detect and network loop prevention allow for chassis to be interconnected without

network issues, stacked chassis are not automatically part of a management group.

See the MX7000 Multi Chassis Management feature for group management. This feature (not covered in this

whitepaper) lets you manage multiple chassis through one management module, and requires the network stacking

arrangement described here.

Recommended Topology for Multiple Chassis

While the auto sensing loop prevention algorithms allow for virtually any topology and provides access to all components

in the stack of chassis, there are optimum topologies for connecting a group of chassis. These topologies provide

redundant connections into the stack and optimize network down time for firmware updates and possible faults. The

cabling diagram shown will protect against any single point of failure in the entire stack. With this configuration you can

survive the following failures and retain full management network access to all nodes in the stack:

Figure 3 – Schematic representation of multiple chassis connections

• Any single network cable failure

• Any single management module failure

• Power loss to any single chassis in the

stack

It is important to note that these are the

minimum failures that we have designed

protection for. It is possible to have more

failures than the above and still have full

functionality, but it would depend heavily

on where those failures occurred.

Here is an example topology for a 12

Chassis Dual MM chassis stack,

connected to a top of rack switch at ports 1

and 4:

For consistent access to all chassis and

their components from a management

network, it is important that both ports 1

and 4 are connected to the same layer 3

network. A very common misconfiguration

that we have seen is accidentally

connecting the two redundant uplink ports

to different VLANs. If the chassis are