Routing Considerations in Mixed Networks

Depending on the topology of the network, there are certain considerations to take into account when activating services. This section highlights the main concerns and steps required to successfully activate services within different network configurations.

GVRP - GARP VLAN Registration Protocol

The Generic Attributes Registration Protocol (GARP) is defined in 802.1D as a means for bridges to distribute information amongst themselves about membership in various groups. 802.1D defines GMRP (GARP Multicast Registration Protocol) to distribute multicast group membership. 802.1Q defines GVRP (GARP VLAN Registration Protocol) to distribute information about VLAN membership.

GVRP addresses the problem of determining which inter-bridge links (NNIs) must be members of which VLANs. In a VLAN-bridge, packets in VLAN x can only be transmitted on links that are members of VLAN x. VLAN x subscriber interfaces (UNIs) are manually configured, but it can be cumbersome to define a VLAN member for all VLANs across all NNIs. One fall-back would be to simply define all VLANs on NNIs, but this means that all flooded packets will be flooded everywhere, which is a large waste of bandwidth.

GVRP, in effect, advertises VLAN membership backwards through the network. If a node must receive packets in VLAN x, it sends a registration for VLAN x to all of its neighbors. Each of those neighbors adds the receiving link to VLAN x and then forwards a registration to all of its neighbors.

Using GVRP lets you dynamically route VLAN traffic through the network and create services without specifying the NNI ports needed for the service.

Mixed Networks - BTI7000 Series with BTI700 Series or BTI800 Series Elements

When a network includes BTI7000 Series packetVX and BTI700 Series or BTI800 Series devices, the topology of the network dictates the NNIs that must be explicitly added to successfully activate a service, regardless of the type of Ethernet service selected. The rule of thumb is that all NNIs on BTI700 Series devices must be added, and all NNIs on BTI7000 Series switches that are facing BTI700 Series devices must be added in order for traffic to flow. Some examples follow.

Note: This section only applies if the Auto-Provision NNIs feature is not selected.

Creating Services in BTI7000 Series packetVX Only Networks

Figure 1: Creating Services in BTI7000 Series packetVX Only Networks

In this case, all network elements are BTI7000 Series packetVX nodes. Only the endpoint UNIs need to be added to the service, as the NNIs will all be GVRP-enabled and the dynamic VLAN creation will automatically route the traffic.

Figure 2: Creating Services in BTI7000 Series packetVX-only Networks

Creating Services Over BTI700 Series And/or BTI800 Series Only Networks

Figure 3: Creating Services Over BTI700 Series And/or BTI800 Series Only Networks

In this case, all network elements are either BTI700 Series or BTI800 Series devices. If the Auto-Provision NNIs feature is disabled, you must explicitly add the NNIs that are part of the service. To avoid single points of failure, it is the user's responsibility to add all NNIs that can form possible paths.

Figure 4: Creating Services Over BTI700 Series And/or BTI800 Series Only Networks

Activating Services Over Combinations Of BTI7000 Series packetVX and BTI700 Series or BTI800 Series Networks

This is a combination of the two previous cases. If the Auto-Provision NNIs feature is disabled, you must add all the NNIs that do not face the GVRP ring (see the table below).

Figure 5: Activating Services Over a Combination Of BTI7000 Series packetVX, BTI700 Series, and BTI800 Series Networks

In this example, NE 1 and NE 2 are BTI700 Series devices, NE 3 through NE 6 are BTI7000 Series packetVX devices, and NE 7 and NE 8 are BTI800 Series devices.