Mac Address Conversion - Cabletron Systems Netlink FRX4000 User Manual

Key Points
MAC Addresses
LAN IDs
LLC2 Function
3-6
When entering a host MAC address in an LLC2 Host or Interface record, enter the
address in non-canonical form unless the attached device is on an 802.3 LAN and the
remote device is on an 802.5 LAN, or the attached device is on an 802.5 LAN and the
remote device is on an 802.3 LAN. In these cases, the incoming address will be "bit-
swapped" by the transmitting host, and you must re-swap the bits before transmission
to the remote device. Bit-swapping is described on
For reference, the following table describes what happens to a MAC address at the
FRX4000/6000 if the sending and receiving formats are different.
Received from: Forwarded to: Action taken:
802.3 802.5
802.3 Native LLC2
802.5 802.3
802.5 Native LLC2
Native LLC2 802.3
Native LLC2 802.5
LAN IDs can be configured in two places:
LLC2 node defaults, to identify a virtual bridge that connects the LLC2 function
to LAN interfaces.
LLC2 frame relay interfaces using 802.5 Source Route Bridge format, to
identify the ring number used by a source-route bridge at the remote end. (This
ID is normally assigned by a system administrator.) Note that the LAN ID on an
originated LLC2 interface must match the LAN ID on the corresponding termi-
nated interface.
Be aware that when configuring these records, LAN IDs must be entered in hex. Also
note that, other than the matching IDs on each originated/terminated interface pair,
each LAN ID must be unique within the network on which the FRX4000/6000 will
operate.
Internally, LLC2 connects to interfaces via the Bridge protocol. LLC2 Host and
Interface records act as both origination and termination points for LLC2. For
example, if you are configuring SDLC-to-LLC2 conversion to be transmitted over
frame relay to a Token Ring host, the following is the logical LLC2 record flow: SNA
Port/PU record (Chapter
as the both the LLC2 Host and LLC2 Interface termination record). In addition, you
must configure an originated Host for the target MAC address, and an interface for the
physical connection.
Table 3-1 MAC Address Conversion
Converts MAC header to LAN header (including cached
RIF), and bit-swaps address
Drops MAC header
Coverts LAN header to MAC header, and bit-swaps address
Drops LAN header
Adds MAC header
Adds LAN header (including cached RIF)
9), with the parameter
LLC2 Connection
page 9-22.
set to
Yes
FRX4000/FRX6000 4.0 User Guide, Rev 01
. (This acts