6 ms·
To clarify, the Arista routers are the ISP's border routers. It was the residential/business customers' SOHO routers, of various makes and models, that were not
by frnkblk 8y ago
To clarify, the Arista routers are the ISP's border routers. It was the residential/business customers' SOHO routers, of various makes and models, that were not decrementing the initial TCP SYN.
- xkgt 8y agoThanks for pointing out. Sorry I overlooked that part. Perhaps I got primed by the opening statements which implied that problem happened only after placing new Arista routers and hastily assumed that it was Arista's routers that mangled the bits.
- frnkblk 8y agoYou are correct, the problem started only after placing new Arista border routers. The previous border routers were not doing ECMP. The issue was a combination of the use of anycast, diverse Internet transit egress, this model of Arista defaulting to using the packet's TTL in its ECMP hash calculations, and the end-customer router CPE egressing packets that are part of the same TCP connection with variable TTL values. Change any one of those items and the issue would not have shown up.