Filter
Top Products
21
CrossFire 8600/8605 Token-Ring Switches v. 1.2, P/N: 710001641 Switch Theory of Operation
There are two levels of relay functions supported by the switch. The first level is
the TrCRF (Token Ring Concentrator Relay Function) to which the ports are
assigned. The second level is the TrBRF (Token Ring Bridge Relay Function). This
is the parent relay function to which TrCRFs are assigned. The switch maintains
certain configuration information and management statistics on a per BRF/CRF
basis. Therefore, when you access VLAN-specific switch configuration or
management screens (such as the
Current Spanning Tree Information
screen),
you will be prompted to specify the desired TrBRF for TrCRF.
Source Route Switching (SRS)
This mode is used between ports comprising a Logical Ring.
SRS switching combines the normal transparent bridge function with the ability to
forward frames based on source route information to locally attached source-route
bridges. The switch does not otherwise act as a source route bridge. For non source-
routed packets, the switch decision is based upon destination MAC Addresses. For
source-routed packets, it is based on the source-route information combined with
the destination MAC address.
The switch learns MAC addresses and source-routing route descriptors of Source
Route Bridges attached to local switch ports.
Parallel paths are eliminated via the IEEE 802.1D Spanning Tree Protocol.
Source Route Bridging (SRB)
The BRF acts as a multiport Source Route Bridge between CRFs with the following
characteristics:
•
Each Logical Ring has a different ring number
•
Source Route Frames are forwarded between the Logical Rings by the Bridge
Relay Function based on the route information field
•
Non-source-route frames are not forwarded between logical rings
•
The Bridge Relay Function has a single bridge number and multiple ring
numbers (one per Logical Ring)
SRS is used between the ports of each logical ring. The Bridge Relay Function runs
the IBM Spanning Tree Protocol to eliminate parallel paths with other source-route
bridges. The IEEE 802.1D Spanning Tree Protocol is still used with each logical
ring. Duplicate MAC addresses are allowed
only
if they are on different Logical
Rings.
Source Route Transparent (SRT)
The BRF can combine transparent switching with Source Route Bridging. Non
source-routed packets are switched across logical rings by transparent bridging.