Feature #137: Add "mtu related problems" section to readme - batman-adv - Open Mesh

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Feature #137

closed

Add "mtu related problems" section to readme

Added by Anonymous almost 15 years ago. Updated almost 8 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Marek Lindner

Target version:

2011.0.0

Start date:

Due date:

% Done:

100%

Estimated time:

Description

As mtu related dropping of packets seems to be the biggest problem using batman-adv it is maybe a good idea to add a small section about it to the readme.

It should have following parts:

Why mtu is lower for bat0

Where packets are dropped in a typical scenario:

client            brigded node1      bridged node2     server
[eth0 (1500)] <-> [eth0 (1500)       [eth0 (1500)  <-> [eth0 (1500)]
                   bat0 (1476)]       bat0 (1476)]
                    ||                 ||
                  [wlan0 (1500)] <-> [wlan0 (1500)]

How it can be tested (ping -M do -s 1472 $IP)
Effects on connections (hangs, connection loss, extreme slow tests with iperf
due to TCP window scaling going wild, ...)
What can be done against it (wlan0: mtu 1524; br0, eth0, bat0: mtu 1500)
Effects of Simons PMTU bridge patch