Very Computer

by **B.D. Deck** » Fri, 10 Jun 1994 11:31:46

Now that I'm all set with CSLIP on both ends of my link, I'd
like to tune my SLIP performance. Currently, using "ifconfig sl0"
regularly gives me statistics similar to the following:

sl0 Link encap AMPR AX.25 HWaddr
inet addr XXX.XXX.XXX.XX P-t-P YYY.YYY.YYY.YY Mask 255.255.0.0
UP POINTOPOINT RUNNING MTU 2000 Metric 0
RX packets 1325 errors 0 dropped 0 overrun 267
TX packets 959 errors 0 dropped 0 overrun 884

If I am reading this correctly, overrun packets are probably a "bad
thing", and should be minimized. I've tried to do that by raising my
MTU, but the kernel gives me kmalloc errors if I go higher than 2000.
Am I looking in the wrong place? Is this possibly a modem problem?

I'm using a USR Sportster with MNP and compression turned on (AT&F1)

--
-.---.----..-.---.----..-.---.----..-.---.----..-.---.----..- --- ----

"Where would you rather be? Anywhere. Anywhere but here" -ORQ

by **mong** » Fri, 10 Jun 1994 13:59:40

: Now that I'm all set with CSLIP on both ends of my link, I'd
: like to tune my SLIP performance. Currently, using "ifconfig sl0"
: regularly gives me statistics similar to the following:

You have something seriously misconfigured if you are using AX.25 with
SLIP and your modem. AX.25 is used for *radio* communication, not used
with dial-up modems usually.
vvvvvvvvvv
: sl0 Link encap AMPR AX.25 HWaddr
: inet addr XXX.XXX.XXX.XX P-t-P YYY.YYY.YYY.YY Mask 255.255.0.0
: UP POINTOPOINT RUNNING MTU 2000 Metric 0
: RX packets 1325 errors 0 dropped 0 overrun 267
: TX packets 959 errors 0 dropped 0 overrun 884

: If I am reading this correctly, overrun packets are probably a "bad
: thing", and should be minimized. I've tried to do that by raising my
: MTU, but the kernel gives me kmalloc errors if I go higher than 2000.
: Am I looking in the wrong place? Is this possibly a modem problem?

Your MTU should not be set any higher than 1500, normally. Some systems
work a lot better with a lower MTU of 1006 or 1024. I don't have SLIP on
Digex, so I can't tell you what they like.

If you are running Linux, you might want to just skip SLIP altogether and
install PPP. It's a much more robust protocol and have the ability to
negotiate with the host for a lot of it's setup parameters.

I am logged in here right now using Linux PPP, via another provider, and
it works very smoothly.

mongo

by **Dan Swartzendrub** » Sat, 11 Jun 1994 09:26:36

>: Now that I'm all set with CSLIP on both ends of my link, I'd
>: like to tune my SLIP performance. Currently, using "ifconfig sl0"
>: regularly gives me statistics similar to the following:

>You have something seriously misconfigured if you are using AX.25 with
>SLIP and your modem. AX.25 is used for *radio* communication, not used
>with dial-up modems usually.

No, this is meaningless. ifconfig seems to always say this, even
when I'm using a perfectly good SLIP connection.

Quote:> vvvvvvvvvv
>: sl0 Link encap AMPR AX.25 HWaddr
>: inet addr XXX.XXX.XXX.XX P-t-P YYY.YYY.YYY.YY Mask 255.255.0.0
>: UP POINTOPOINT RUNNING MTU 2000 Metric 0
>: RX packets 1325 errors 0 dropped 0 overrun 267
>: TX packets 959 errors 0 dropped 0 overrun 884

>: If I am reading this correctly, overrun packets are probably a "bad
>: thing", and should be minimized. I've tried to do that by raising my
>: MTU, but the kernel gives me kmalloc errors if I go higher than 2000.
>: Am I looking in the wrong place? Is this possibly a modem problem?

>Your MTU should not be set any higher than 1500, normally. Some systems
>work a lot better with a lower MTU of 1006 or 1024. I don't have SLIP on
>Digex, so I can't tell you what they like.

This is not a problem either. The overrun field is actually
referring to compressed packets. Alan had to reuse a variable
or something.
--

#include <std_disclaimer.h>

Dan S.

by **Andrew Robins** » Sun, 12 Jun 1994 07:31:39

>: Now that I'm all set with CSLIP on both ends of my link, I'd
>: like to tune my SLIP performance. Currently, using "ifconfig sl0"
>: regularly gives me statistics similar to the following:
>You have something seriously misconfigured if you are using AX.25 with
>SLIP and your modem. AX.25 is used for *radio* communication, not used
>with dial-up modems usually.
vvvvvvvvvv
>: sl0 Link encap AMPR AX.25 HWaddr
>: inet addr XXX.XXX.XXX.XX P-t-P YYY.YYY.YYY.YY Mask 255.255.0.0

Actually, it looks like an older version of ifconfig is being used with a
newer kernel. I was surprised myself when I was running SLIP, typed
'ifconfig' and saw "AX.25". Upgrading to the newer version of ifconfig and
route solved the problem (actually, it worked just fine, it only reported
wrong).

--
Andrew Robinson

Very Computer

CSLIP sl0 Performance

CSLIP sl0 Performance

CSLIP sl0 Performance

CSLIP sl0 Performance

CSLIP sl0 Performance