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List:       linux-atm
Subject:    Re: Max write to socket (and lane)
From:       Ken Sailor <sailor () salph1 ! sask ! trlabs ! ca>
Date:       1997-11-27 15:18:28
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Vinay,

I'm writing to a native PVC, not using IP.  Do the IP limits apply to all 
sockets?  How would I change the number?  

On Solaris with a fore sba-200 I have the program atmconfig to change the 
mtu, but changing the mtu does not change the size I can write to in the 
socket.

Ken

------------------------------------------------------------------
Ken Sailor				sailor@cs.usask.ca
                                        sailor@sask.trlabs.ca

HyperCore Technology Inc.		University of Saskatchewan	
Senior Software Analyst			Adjunct Professor
phone 1-306-668-8218			fax 1-306-668-1944



On Mon, 24 Nov 1997 bannai@best.com wrote:

> According to Ken Sailor:
> > Actually this is two separate messages (or questions).
> > 
> > I experience a maximum write to an atm socket (or read) of 1000 bytes.  (Best
> > effort, AAL5).  Is there a reason for this limit?  I was thinking of the max
> > PDU size of 65K for aal5 and surprised at the low limit.  (This is using
> > version 31 and efficient ENI-155's).  I checked out my Fore card on a solaris
> > box, and it max'ed out at 9184 bytes (which plus the 8 trailer bytes makes
> > 2^13) -- which also falls pretty far short of the aal5 max.
> 
> You are not able to write more than 1000 bytes at a time? Does the socket
> write operation return an error when you try to write more than 1000
> bytes? 
> 
> The default MTU size of a AAL5 PDU over IP is 9180 bytes. This is the
> default specified in the RFC's and most widely used MTU. You can change it
> to any number between 1 and 64K - 1. I think the reason for this number
> has to do with the NFS. NFS uses default chunk size of 8K for data
> transfer. Also it has to do with something related to SMDS, where the MTU
> is also 9180 bytes. I don't know the exact reason.
> 
> Vinay
> 
> > 
> > Secondly, any advice on the state of LANE for the current release?  If I were
> > to talk my boss into letting me help with the conversion, what could I do to
> > help?  Would it be a fairly mechanical matter of changing a variety of calls
> > to match new formats, or would the code require more extensive rewrites? (or
> > redesign?)
> > 
> > Ken
> > 
> 
> 

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