Firewall Wizards mailing list archives
RE: IPSEC over load-shared T1s (per packet)
From: "Jan Bervar" <jan () nil si>
Date: Mon, 22 Sep 2003 09:17:11 +0200
Just my 0.02 EUR... MPPP can be performance intensive on routers, and your ISP may not be willing to implement it at all. Cisco routers can also load-balance on a source-destination hash, which means that ideally, L3 sessions are evenly balanced across a number of links. In a VPN scenario, this works much better compared to per-destination balancing, especially if the number of your VPN peers is large and dynamically addressed. Both sides of the link(s) need to enable Cisco Express Forwarding, and there is no significant perfomance hit involved (provided their and your routers have the memory to handle CEF tables). Cheers, Jan firewall-wizards-admin () honor icsalabs com wrote on 20.09.2003 05:51:54:
I think this is pretty much solved now, but just for the sake of the archives: The problem was pretty much as I guessed (just lucky ;). The packets were being sent over alternating links in strict
round-robin,
which meant that the ESP packets sometimes arrived out of sequence. The IPSec implementation was dropping all the ones with seq < currentseq,
which
was causing retransmits in the tunneled TCP sessions. One fix is to use "per destination" load balancing - but that is bad
because
if all the traffic is VPN then only one link will get used (only one destination). What I suggested offlist is to look at either ppp-multilink, or
MUX/DE-MUX -
both of those will make the link look like one big layer2 pipe, which
will
fix the problem and preserve sequencing. PPP Multilink is software, and simple. MUX stuff is more complicated but faster and can be more
flexible.
I also got queries offlist about the E1/T1 RJ connectors. Yes, I did,
OK? I
was curious. Ow.
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Current thread:
- IPSEC over load-shared T1s (per packet) TSimons (Sep 18)
- RE: IPSEC over load-shared T1s (per packet) Ben Nagy (Sep 19)
- RE: IPSEC over load-shared T1s (per packet) R. DuFresne (Sep 19)
- RE: IPSEC over load-shared T1s (per packet) Ben Nagy (Sep 19)
- Re: IPSEC over load-shared T1s (per packet) Mikael Olsson (Sep 19)
- RE: IPSEC over load-shared T1s (per packet) Jan Bervar (Sep 22)
- Message not available
- RE: IPSEC over load-shared T1s (per packet) Pano Xinos (Sep 23)
- RE: IPSEC over load-shared T1s (per packet) R. DuFresne (Sep 19)
- RE: IPSEC over load-shared T1s (per packet) Ben Nagy (Sep 19)
- <Possible follow-ups>
- RE: IPSEC over load-shared T1s (per packet) TSimons (Sep 19)
- RE: IPSEC over load-shared T1s (per packet) TSimons (Sep 19)
- RE: IPSEC over load-shared T1s (per packet) TSimons (Sep 22)