Installation guide

A Sample VLAN Topology

Chapter 7

In the simplest terms, a VLAN is a user-defined set of these ports, grouped together such that they live in the

same subnet. A VLAN can be given an IP address that serves as an endpoint (or destination) for outside

traffic, or it may live anonymously within the Switch Blade and rely on established switch routing to send or

receive traffic on an anonymous VLAN.

Network Interfaces Partitions

The best way to think about partitioning the network interfaces is by modeling the intended use-cases. The

objective is to let the use-cases define the topology, and to let the topology define the VLANs you need to

create in your Ethernet Switch Blades. For this sample topology, there are three main use-cases:

• Walk-up Configuration LAN: The Switch Blade OOB ports should be set up for walk-up configuration

purposes only; that is, to allow you to plug a laptop computer into the Switch Blade in order to gain access

to the Switch Blade configuration commands. The intent is that the OOB ports are protected by the

physical security imposed on the 14-Slot Shelf unit.

IMPORTANT These OOB LAN ports on the Switch Blades should never be plugged into an enterprise

network.

• Management LAN: One base interface (the raw Ethernet connection zre12 that is exposed on the front

panel of the Switch Blade) is configured to support all the functions required for managing the 14-Slot

Shelf remotely. Management protocols such as SNMP, IPMI, and PXE send their traffic on the

management LAN. The management LAN is intended to be connected to the designated management

network within the enterprise. The remaining base interfaces (zre0 to 11, zre14 to 21) are configured into

a single VLAN in order to provide control-plane connectivity to all blades in the 14-Slot Shelf.

• Payload LAN: The fabric interfaces (zre0 to 51 fabric) are configured for bearer or payload traffic - that

is, application traffic requiring intra- and inter-shelf networking.

Other use-cases center on the switch-to-switch traffic (between Ethernet Switch Blades), and on the traffic

from the Ethernet Switch Blades to the Shelf Managers (ShMMs). Each use-case defines another part of this

sample network topology:

• Switch-to-Switch LAN: Creates a private network that enables the two Switch Blades to talk to each

another. This link is called the Inter-Switch Link (ISL), and accomplishes three goals:

— Traffic hitting one Switch Blade can see the network devices connected to the other Switch Blade.

— Each Switch Blade can see the active ShMM at all times.

— This LAN is also needed for High Availablility (HA) operation.

NOTE This VLAN contains raw Ethernet connections zre22 and zre23; zre22 connects the

Switch Blade to the same-side ShMM, and zre23 is the Inter-Switch link (ISL) between

the two Switch Blades.

• ShMM Cross-connect LAN:

Creates a private network on each Ethernet Switch Blade connecting to the opposite-side ShMM by

configuring the eth1 interface of each ShMM. The zre13 port allows you to talk from the Switch Blade to

the opposite-side ShMM. This subnet, in combination with the switch-to-switch LAN above, guarantees

that each Switch Blade can always talk directly to the active ShMM - even if one of the Ethernet Switch

Blades were to fail, and the active ShMM is on the opposite-side of the surviving Switch Blade.