QRZ! Ham Radio 5/QRZ Ham Radio Callsign Database - Volume 5.iso/digests/tcp/940191.txt

Internet Message Format | 1994-11-13 | 5.5 KB

Date: Fri,  2 Sep 94 04:30:03 PDT
From: Advanced Amateur Radio Networking Group <[e-mail]>
Errors-To: [e-mail]
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Subject: TCP-Group Digest V94 #191
To: tcp-group-digest


TCP-Group Digest            Fri,  2 Sep 94       Volume 94 : Issue  191

Today's Topics:
                            encapsulation
                      encapsulation and port #'s
                            Encapsulations
                      TCP-Group Digest V94 #189
         TCP-Group Digest V94 #189 (NOS sizeups as a router)

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Date: Thu, 01 Sep 94 09:47:20
From: [e-mail]
Subject: encapsulation
To: [e-mail]

There are two rfc's that cover ipip encapsulation,
rfc1226 and rfc1241,
I believe it is 1241 that is authored by our very own Brian Kantor and deals
with AX25 specifically. The other deals with generic ipip encap.
I don't know to what extent the NOS implementation maps to these, except the
port number is mentioned in the rfc as 93, not 94.

Walt

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Date: Thu, 01 Sep 94 10:09:30
From: [e-mail]
Subject: encapsulation and port #'s
To: [e-mail]

So could some one unconfuse me (direct mail please) as to the history of
RFC's on this and the current port 94 to port 4 switch.

Jack
KD4IZ
[phone]

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Date: Thu, 1 Sep 1994 12:46:09 +0200 (BST)
From: [e-mail] (Alan Cox)
Subject: Encapsulations
To: [e-mail]

I raised the issue of IP encapsulation over AX.25 and possible mapping
strategies in amongst some examples on the IPng discussion list. This lead
to the suggestion someone ('how about you ?') ought to write this up and
submit it. Now I'm happy to do this and post drafts onto here but I don't
want to step on any feet, and it seems people like Phil or Brian ought to
be the ones who have first option on doing this and also probably have a
few better ideas 8)

Thoughts ?

Alan

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Date: Thu, 1 Sep 1994 20:41:15 -0700
From: Phil Karn <[e-mail]>
Subject: TCP-Group Digest V94 #189
To: [e-mail]

>You've got to be kidding. I need to run KA9Q because it has an 'encap'
>interface (tunneling IP over IP) for gateways, and I can easily hang a
>KA9Q router.  For example, a wayward RPC program can go nuts sending
>out udp packets to portmap on a machine on the other end, instant
>sieze up of the NOS router. Or (so I'm told) run xmaze through a KA9Q
>box that's routing to a 56kbps tcp/ip packet network, one or two mazes
>get drawn and the NOS box dies. Maybe NOS just doesn't like UDP.

This doesn't make any sense, at least not if NOS is just routing the
UDP packets. A router doesn't even look beyond the IP headers of the
packets it routes.

My NOS router at home stays up for months at a time, despite heavy
daily use (from my BSDI box) for just about every protocol in the
suite - Telnet, FTP, rlogin, X, NFS, DNS, NNTP, SMTP, you name it.

Maybe the problem is that people are trying to add too much
application cruft to NOS instead of using it as the simple low-end
router it was designed to be.

Phil

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Date: Fri, 2 Sep 1994 02:17:06 -0500
From: "Milton D. Miller II" <[e-mail]>
Subject: TCP-Group Digest V94 #189 (NOS sizeups as a router)
To: [e-mail]

>From [e-mail] Thu Sep  1 23:59:40 1994
>Date: Thu, 1 Sep 1994 20:41:15 -0700
>From: Phil Karn <[e-mail]>
>To: [e-mail]
>CC: [e-mail]
>In-reply-to: <[e-mail]> ([e-mail])
>Subject: Re: TCP-Group Digest V94 #189

>>You've got to be kidding. I need to run KA9Q because it has an 'encap'
>>interface (tunneling IP over IP) for gateways, and I can easily hang a
>>KA9Q router.  For example, a wayward RPC program can go nuts sending
>>out udp packets to portmap on a machine on the other end, instant
>>sieze up of the NOS router. Or (so I'm told) run xmaze through a KA9Q
>>box that's routing to a 56kbps tcp/ip packet network, one or two mazes
>>get drawn and the NOS box dies. Maybe NOS just doesn't like UDP.

>This doesn't make any sense, at least not if NOS is just routing the
>UDP packets. A router doesn't even look beyond the IP headers of the
>packets it routes.

My first response to the original posting is "ohh... he is talking
about the problem that NOS never discards incoming packets, but
instead buffers them up until they get routed and sent out.  Even
if there is not enough memory left to do the necessary copies to
send a packet out." problem.

One way to help reduce the problem is to limit the number of interrupt
pool buffers to the reasonable burst rate for the incoming wire.  The
burst gets used up, but the rest are dropped until the queue is refreshed
during the normal timer processing.  Of course, not compiling the unneeded
services helps also :-).

milton
--
Milton Miller  KB5TKF  [e-mail]

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End of TCP-Group Digest V94 #191
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