We have a dedicated 155Mbit ATM network for ADSM backups. We are using
Classical IP over ATM not LAN Emulation. The clients consist of HP-UX and
AIX servers which all connect to two Cisco ATM switches. The switches
connect to a Cisco Router which is attached to the MVS system via and ESCON
channel using a Cisco CIP card in the router. We went with Classical IP
instead of LANE because the HP and IBM network interface cards in the UNIX
boxes only supported Classical IP. Throughput is about 3.5MB to 4MB per
second using FTP. We are using TCP/IP offload with the CIP card and
suspect we may see better throughput when we upgrade from MVS TCP/IP 3.1 to
3.2 also. I have also purchased an IBM 2216 Multi-access connector(IBM
router) to be used as a dedicated gateway for sending ADSM backups over the
same ATM LAN to MVS. This will provide me with multiple paths into the
mainframe for ADSM data. During my evaluation of the 2216 I was able to get
around 5MB/sec with FTP. The Cisco uses the CLAW for it's mainframe
communications and is limited to a 4k MTU/packet size. Since we were using
offload with the CIP the maximum value we could used for
DATABUFFERPOOLSIZE on MVS TCP/IP was 32k. The 2216 doesn't use CLAW and
the MTU in our case was limited by the UNIX client which max allowed is 9k.
I could also use a DATABUFFERPOOLSIZE of 262k in MVS TCP/IP with the 2216
and performance got better each time I increased the buffers up to that
value. The 2216 also attaches to the MVS system via an ESCON channel and
you can have up to four channels per 2216. The work can be load balanced
across the ESCON channels. The 2216 supports most network attachments,
155Mbit ATM, Faster Ethernet, Ethernet, Token-ring, etc. To me, based on
cost and performance, the 2216 was a better deal than buying an additional
Cisco CIP for another router. Hopefully it will turn out to be a good
choice.
We also have an OSA-2 but have been unable to use it since the ATM OSA-2
only supports LAN Emulation. I've been told that Classical IP support is
coming 1Q98. I've also heard that in general you can get better
performance using Classical IP than with LANE. Although I have no way of
proving that and it's not my area of expertise so I don't know how much
truth there is to that statement. Hope this helps.. If you need more
detail let me know at CONNORJ AT NIMO DOT COM.
Other Background:
ADSM for MVS v2.1.10
MVS 4.2.2 on a 9672-R54
TCP/IP for MVS v3.1
AIX Clients 4.1.4 ADSM ptf level 6
HPUX Clients 10.20 ADSM ptf level 6
Jeff Connor
Systems Programmer
Niagara Mohawk Power Corp
Syracuse, NY
HRubin AT MOBILE.BAM DOT COM
10/22/97 09:58 AM
Please respond to ADSM-L AT VM.MARIST DOT EDU
To: ADSM-L AT VM.MARIST DOT EDU
cc: (bcc: Jeffrey P Connor)
Subject: ADSM & ATM
Is anyone using an ADSM on an ATM network with MVS as the ADSM server and
AIX or Solaris as the clients?? If so, what methods are you using to
connect your mainframe to the ATM network?
We are building a dedicated network for our ADSM backups to our IBM
mainframe. We had planned on 155 Mbit ATM, but it appears that there may
be a bottle-neck either with the TCP/IP stack (IBM), or with the OSA
adapter that we have the ATM card plugged in to.
More details:
ADSM version: 2.1.0.6
ADSM server: IBM CMOS
mainframe running
OS/390
Network Interface (mainframe): OSA-2
ATM switch vendor: Xylan
ADSM clients: AIX 4.21,
Solaris 2.51
Method used for testing: FTP
ATM Physical Layer: SONET / OC-3
ATM Logical Layer: LAN Emulation
Measured throughput: Mainframe -> SUN
14
Mbits/sec
SUN -> Mainframe 15
Mbits/sec
Any insight is appreciated.
Please post reply to ADSM-L AT VM.MARIST DOT EDU or directly to me at
hrubin AT mobile.bam DOT com
Harold
+--------------------------------------------+
| Harold Rubin |
| Senior Member of Technical Staff - UNIX |
| Bell Atlantic Mobile |
| 2000 Corporate Drive, Orangeburg, NY 10962 |
| Phone: 914-365-7338 Fax: 914-365-5937 |
| e-mail: hrubin AT mobile.bam DOT com |
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