Re:Service provider story about tracking down TCP RSTs
by toast0 on Sunday September 02, 2018 @11:20PM
(#17900077)
The problem is if all of the equipment hashes the same way, many of your links will be underutilized.
If A has a link to B1 and B2, and each of B1 and B2 have two links to C, and everything hashes the same, there will only be two possible paths to C, instead of the four you should have.
Ex: if packet hashes to 0, it goes to B1, and then over the 0 link to C. If packet hashes to 1, it goes to B2 and over the 1 link to C. If the Bs hash on different values than A (including if they have a different salt), you'll have better distribution on the B to C links, and actually be able to hit all 4 paths.
If A has a link to B1 and B2, and each of B1 and B2 have two links to C, and everything hashes the same, there will only be two possible paths to C, instead of the four you should have.
Ex: if packet hashes to 0, it goes to B1, and then over the 0 link to C. If packet hashes to 1, it goes to B2 and over the 1 link to C. If the Bs hash on different values than A (including if they have a different salt), you'll have better distribution on the B to C links, and actually be able to hit all 4 paths.