Repository : ssh://git@open-mesh.org/doc

On branches: backup-redmine/2017-07-13,master

commit 3cffaaa86c9c67dcec217299b4637f6ac4a5fb84 Author: Sven Eckelmann sven@narfation.org Date: Sat Mar 26 22:15:17 2011 +0000

doc: batman-adv/Bcast-hidden-node

3cffaaa86c9c67dcec217299b4637f6ac4a5fb84 batman-adv/Bcast-hidden-node.textile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/batman-adv/Bcast-hidden-node.textile b/batman-adv/Bcast-hidden-node.textile index 2d05f5e5..4b31ad98 100644 --- a/batman-adv/Bcast-hidden-node.textile +++ b/batman-adv/Bcast-hidden-node.textile @@ -5,7 +5,7 @@ See "here":http://en.wikipedia.org/wiki/Hidden_node for a general description of

h1. Hidden Node Problem and NDP/OGMs

-Especially in indoor scenarios like the one shown below where corners and thick walls are involved, hidden nodes can be a severe problem. Usually activating "RTS/CTS":http://en.wikipedia.org/wiki/802.11_RTS/CTS is a common way of solving this problem at least to some degree. However, "RTS/CTS":http://en.wikipedia.org/wiki/802.11_RTS/CTS can only be applied for unicast packets. Therefore a node C sending a lot of data packets to B, even with RTS/CTS those packets will interfere with BATMAN's broadcast packets (e.g. "NDP":http://www.open-mesh.org/wiki/batman-adv-ndp packets or OGMs). The effect is, that with this stream, only the TQ from A -> B will decrease dramatically, the rest will stay relatively equal. +Especially in indoor scenarios like the one shown below where corners and thick walls are involved, hidden nodes can be a severe problem. Usually activating "RTS/CTS":http://en.wikipedia.org/wiki/802.11_RTS/CTS is a common way of solving this problem at least to some degree. However, "RTS/CTS":http://en.wikipedia.org/wiki/802.11_RTS/CTS can only be applied for unicast packets. Therefore a node C sending a lot of data packets to B, even with RTS/CTS those packets will interfere with BATMAN's broadcast packets (e.g. [[batman-adv-ndp|NDP]] packets or OGMs). The effect is, that with this stream, only the TQ from A -> B will decrease dramatically, the rest will stay relatively equal.

In the worst case, this can lead to route flapping to the shorter path, due to all these lost packets, A will switch its route towards C to the direct one if occasionally some NDP/OGMs had been received over this link, which might however not be usable for i.e. TCP traffic due to a too high packet loss.