On Tue, Apr 24, 2001 at 02:42:16PM +0200, Cesare Fontana wrote: > Samuele Giovanni Tonon wrote: > > il problema e' ECN (Explicti Congestion Notification ) > > echo 0 > /proc/sys/net/ipv4/tcp_ecn e puoi usarlo anche con in 2.4.x > io non ho il 2.4.x... ma sono curioso di sapere cosa è sta cosa...
Explicit Congestion Notification (CONFIG_INET_ECN). l'help del kernel mi sembra abbastanza chiaro su quella opzione. Anche cercando CONFIG_INET_ECN con google la prima cosa che si becca e` uno sostanzialmente con lo stesso problema anzi la risposta che ripete l'help del kernel: [SNIP] Note that, on the Internet, there are many broken firewalls which refuse connections from ECN-enabled machines, and it may be a while before these firewalls are fixed. [SNIP] Explicit Congestion Notification is more fully documented in RFC2481. Da altre cose con la stessa ricerca in google: * From: Gregory Maxwell <greg(a)linuxpower.cx> * Date: Mon, 30 Oct 2000 23:36:38 -0500 The sites are broken. They are running crap firewalls (often Cisco) that probably haven't been updated (or have no update available), and they see the (perfectly standards compliant) 'I support ECN' flag, think it must be something evil and drop the packet silently. ECN is an important factor for the future scalability of the Internet. It allows for much smarter methods for congestion control. It's important that it get implemented, but these crappy firewalls are standing in the way. ------- * From: "David S. Miller" <davem(a)redhat.com> * Date: Mon, 30 Oct 2000 20:16:52 -0800 What exactly does "Explicit Congestion Notification" do? It's a protocol extension by which routers can tell clients about the onset of congestion before the routers stops to drop that client's packets. Unfortunately, a widely deployed firewall product made by Cisco and used at most of the large web sites block packets that make use of ECN. They have fixed the bug, but I honestly don't expect these sites to install the fix any time soon no matter how much the Cisco folks tell me that such sites are "likely to".
