ITEM: CC3620L

how do you connect a RAN to a frame relay router


env:    AIX 3.2.5
        7013-59h

desc:
        We want to attach a remote RAN from a 128-port
        over a frame relay router
ACT:
        This if a fax document sent out by Digiboard on the topic of
        remote RAN over frame relay:

PRODUCT: C/X,   EPC/X   (IBM RAN)

Index:  120595ckd

Problem: How do I configure my C/X to work remotely with frame relay?

Solution:

The Digi C/X concentrator family can be configured for remote operation
using frame relay as the interconnect layer.

Digi uses HDLC framing on the synchronous data link between the
concentratores and the host adapter.  However, we do not use SDLC 
protocol for the data transmission.  We use a proprietary protocol.
This means that a FRAD can be configured to send the packets to the 
correct Frame relay PVC, but the FRAD can not be configured to read
the SDLC address and direct each packet to a particular PVC.  Because
of this limitation, the FRAD attached to each device (host adapter or
concentrator) must be hard configured to map packets to a particular
destination PVC.

Under the above configuration limits, only one remote location can be
supported attached to a host adapter port.  For instance, if there are 6
remote locations containing concentrators, six host adapters would
be required at the host system.

All digi products (host adapters and concentrators) should be configured
to receive clocks from the FRAD's.  The configuration string should be 
set to a baud rate below that of the FRAD synchronous line.  This will
not change the data transmission rate since the devices receive their
clocks from the FRAD, but the synchronous link will be configured with
longer timeouts and smaller packets.  This is often required because of
longer latency in a frame relay cloud compared to our dedicated 
synchronous link.

Please be careful of the required bandwidth of the frame relay links.
It is common to have 56k frame relay connections at the remote sites.
This will support six 9600 baud connections without flow controlling
the devices.  If the customer is using a multiconnection FRAD at the 
host end, the host end  frame relay link will have to be equal or 
greater than the total of the bandwith of the end points to avoid 
congestion under heavy load.  This will most likely require a T1 or
fractional T1 line at the host end of the frame relay cloud.


Support Line: how do you connect a RAN to a frame relay router ITEM: CC3620L
Dated: August 1996 Category: N/A
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