9 Mar
2016
9 Mar
'16
7:40 a.m.
And there comes nice feature
of ampr-ripd program by Marius YO2LOJ:
in case of missing or not broadcasted
RIPv4 transmission, it keeps LASTLY
received data, thus preserving routing table.
But of course only for completely lost transmissions.
Some time ago I was hunting a problem where I apparently had packet loss in RIP
transmissions, likely because they are sent in a big burst and may overflow buffers or
exceed
rate limits somewhere. In that case I was randomly losing routes. I kind of fixed that
by
increasing the timeout on routes to two hours (default was much lower, 15 minutes I
think).
Also when something would break down that resulted in e.g. the RIP server sending only
info
about 44.0.0.0/8 in a single packet and not all the other gateways (e.g. due to an empty
result from a database query due to some outside issue), the routes would still be lost.
It is always difficult to prevent all possible mishaps. Sending updates from different
sources will also not prevent all problems (after all there must be a single source of
all
the info that is being distributed, or we would be faced with two portal systems and the
obligation to always register and update both).
Rob
9 Mar
9 Mar
8:37 a.m.
New subject: Is there raceroutre machine on 44 net available forpublic ?
I've never found the cause of this; the rip sender would report protocol
buffer overflows and never has. The UCSD network can easily take the
amount of traffic that the rip transmissions constitute, and is not rate
limited, so I am led to the conclusion that the loss must be along the
transit path somewhere. Of course, being UDP inside IP, we don't get
notified of in-transit packet drops so it remains a mystery why this
is/was happening.
I had considered using TCP connections to transmit the data for
reliability but didn't want the time and overhead of establishing a
fresh connection to each gateway system and then closing it, once for
each gateway every five minutes. Starting up and knocking down TCP
takes time. The delay waiting for a down gateway connection to time out
would be a killer. And make no mistake, lots of gateways are offline
at any particular time.
Nor did long-duration connections seem practical; the amount of program
logic and memory to maintain and re-establish them is non-trivial,
and I'm not sure it's practical to maintain three to four hundred TCP
connections for days or months at a time on a small machine like amprgw.
- Brian
On Wed, Mar 09, 2016 at 01:40:46PM +0100, Rob Janssen wrote:
Some time ago I was hunting a problem where I
apparently had packet loss in RIP
transmissions, likely because they are sent in a big burst and may overflow buffers or
exceed
rate limits somewhere. In that case I was randomly losing routes. I kind of fixed that
by
increasing the timeout on routes to two hours (default was much lower, 15 minutes I
think).
9:22 a.m.
New subject: Is there raceroutre machine on 44 net available forpublic ?
I concur with Brian and Rob observations.
Two years ago I was taken aback by the
fact that my routing table suddenly contained
roughly just HALF of it's regular entries.
Searching for troublemaker I discovered,
that because I used ALL data transfer limits,
local ISP GSM provider cut down connection
speed so significantly that RIP broadcasts
weren't coming through in full size...!
Best regards.
---
Tom - SP2L
Sent from Xperia Z1 with AquaMail
http://www.aqua-mail.com
10 Mar
10 Mar
1:33 a.m.
New subject: Is there raceroutre machine on 44 net available forpublic ?
If the only problem is a stronger computer it can be solved
Im (almost) sure that every one of us will be able to donate in order to buy the right
computer for the task
Ronen - 4Z4ZQ
http://www.ronen.org
________________________________________
From: 44Net <44net-bounces+ronenp=hotmail.com(a)hamradio.ucsd.edu> on behalf of Brian
Kantor <Brian(a)UCSD.Edu>
Sent: Wednesday, March 9, 2016 5:37 AM
To: AMPRNet working group
Subject: Re: [44net] Is there raceroutre machine on 44 net available forpublic ?
(Please trim inclusions from previous messages)
_______________________________________________
and I'm not sure it's practical to maintain three to four hundred TCP
connections for days or months at a time on a small machine like amprgw.
- Brian
2991
days inactive
2992
days old
3 comments
4 participants
participants (4)
-
Brian Kantor -
R P -
Rob Janssen -
SP2L Tom