User`s guide

5 - 4 Ethernet or Token Ring Bridge

Setting the Routing Method (Method) Token Ring Only

The Token Ring Bridge may be conﬁgured to operate with networks:

n Whose packets are transparently routed by Bridges based on the

destination MAC address.

n Whose packets must contain a source routing mode header to guide

their path through the infrastructure.

Transparent:

It is assumed that there are no source routing headers in the packets. The

unit will monitor all packets sent around the Token Ring infrastructure.

Only packets with destination addresses that match the address of a

radio node associated to the Token Ring Bridge or multicasts will be

forwarded out to the radio. No source routing header will be added to

any packets sent out the Token Ring Bridge.

Source routing:

The unit must watch all trafﬁc on the LAN.

The packet will be forwarded to a radio network if:

n The unit identiﬁes a packet with a source route that ends at the ring

number on which the unit is located

n The destination address belongs to a radio mode

n The destination is a multicast

The unit will also record the source route back to the originator of the

packet for later use. Since all radio nodes are conﬁgured as though they

are connected to an Ethernet LAN (which always uses transparent rout-

ing), the Token Ring Bridge must add source routes to any outgoing

packets. If the destination is in the list of learned routes, the route is

used, otherwise the packet is sent with a broadcast route. Once the desti-

nation responds, the Token Ring Bridge will learn the new address.