From d8440aac9e6e279867677daf7e9db8263875cae9 Mon Sep 17 00:00:00 2001 From: Dmitry Tantsur Date: Wed, 11 Sep 2024 17:37:24 +0200 Subject: [PATCH] Try limiting MTU to at least 1280 Change-Id: If8f9907df62019b3cf6d6df7d83d5ff421f6be65 (cherry picked from commit 510f87a033ce5f76a7aa881f56b2bd9958c8582f) --- devstack/settings | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/devstack/settings b/devstack/settings index 2f77dadf20..b40d6e127e 100644 --- a/devstack/settings +++ b/devstack/settings @@ -22,9 +22,12 @@ if [ $local_mtu -gt $PUBLIC_BRIDGE_MTU ]; then fi # 50 bytes is overhead for vxlan (which is greater than GRE -# allowing us to use either overlay option with this MTU. +# allowing us to use either overlay option with this MTU). # However, if traffic is flowing over IPv6 tunnels, then -# The overhead is essentially another 100 bytes. In order to +# The overhead is essentially another 78 bytes. In order to # handle both cases, lets go ahead and drop the maximum by -# 100 bytes. -PUBLIC_BRIDGE_MTU=${OVERRIDE_PUBLIC_BRIDGE_MTU:-$((local_mtu - 100))} +# 78 bytes, while not going below 1280 to make IPv6 work at all. +PUBLIC_BRIDGE_MTU=${OVERRIDE_PUBLIC_BRIDGE_MTU:-$((local_mtu - 78))} +if [ $PUBLIC_BRIDGE_MTU -lt 1280 ]; then + PUBLIC_BRIDGE_MTU=1280 +fi