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Feature #137

closed

Add "mtu related problems" section to readme

Added by Anonymous about 14 years ago. Updated about 7 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Target version:
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
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