Frame Relay vs Modems to Connect remote RANs?
ITEM: RTA000150393
Q:
Customer wants to use a frame relay network vs a point-to-point modem
leased line to install a remote RAN on a 128port controller, using the
appropriate model of 2218. Is this supported?? If so, could you
provide a drawing and the appropriate model of 2218???
If not, would you please render a high level explanation as to the
technical reason??
A:
IBM does not support nor have pin-out cabling information on connecting
a 128port adapter, (Digi reference EPC/X), to a Frame relay unit.
The following document was acquired from Digi Board who makes the
128port adapter:
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
concentrators 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.
Specific pin out infomation could possibly be aquired from
DIGI working with those people intimate with the FRAME RELAY
equipment. DIGI's phone:
Customer Service/Technical Support: (612) 912-3456
IBM can support getting the adapter itself available on the RS6000,
but connection to, and data transmission across, FRAME RELAY equipment
is done by the equipment manufacture.
WWQA: ITEM: RTA000150393 ITEM: RTA000150393
Dated: 06/1998 Category: RISCAPRT
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