Hi,
How would you loadshare over many (>6) parallel E1 links. Currently we
do it by connecting them directly to the Cisco's in each end, and do
CEF based per-packet loadsharing, it works fine, but support a max of
6 E1's ...
I've been thinking om something similar to the Larscom inverse MUX
(http://www.larscom.com/t3ft3/t3_megae.htm), but this one only support
4 E1's, then I can use multiple i-mux's and loadshare over the 8M links
they provide, but it seems like a poor solution.
Yes, I do know that a E3 would be a far better choice, but our ADM
(Add-Drop-Multiplexer??) at this specific location only support
E1's 
/Jesper
Jesper,
You might consider MLP (multi-link PPP), with VIP2/50's.
If you do go with an IMUX, I definitely recommend a HSSI to the routers, rather than Ethernet, unless the Ethernet is full-duplex. I've seen really poor performance due to collisions on the Ethernets at either end because the middle is actually 16Mbps full-duplex...
Scott
This is a problem because igp issues:
nnn-7202(config)#router ospf 1
nnn-7202(config-router)#maximum-paths ?
<1-6> Number of paths
Because of this, you are unable to hanle those multiple paths
past 6.
You also have the same isues with isis:
nnn-7202(config)#router isis home1
nnn-7202(config-router)#maximum-paths ?
<1-6> Number of paths
I don't have a pdf viewer (on this machine), so can't cite this
right now, but I think that the dl imux will handle up to 8 E1's:
http://www.dl.com/online/datashts/dl3800e.pdf
- jared
In article <19980918095708.B10051@skriver.dk> you write:
How would you loadshare over many (>6) parallel E1 links. Currently we
do it by connecting them directly to the Cisco's in each end, and do
CEF based per-packet loadsharing, it works fine, but support a max of
6 E1's ...
Cisco has a nice white paper on this:
http://www.cisco.com/warp/public/733/adap/multi/althb_wp.htm
I think Multilink PPP may be your answer, as it goes
up to 8 links. There is a CPU hit though, I've never tried
Multilink on a high speed interface so I don't know how bad
it might affect the router.
Jared Mauch wrote:
I don't have a pdf viewer (on this machine), so can't cite this
right now, but I think that the dl imux will handle up to 8 E1's:
You might want to check into the 3com ab6200 as well. It's the only box we
could find on the market that can imux more than 8 T1's (I assume it can do E1's
as well). They say it should work up to 56 T1's, but you're out of HSSI
bandwidth long before then of course. We're using it for 11 T1's imuxed right
now and it seems to work fine.
How would you loadshare over many (>6) parallel E1 links. [...]
I've been thinking om something similar to the Larscom inverse MUX
(http://www.larscom.com/t3ft3/t3_megae.htm), but this one only support
4 E1's, then I can use multiple i-mux's and loadshare over the 8M links
they provide, but it seems like a poor solution.
We use Larscom Orion 4000s for 6 transatlantic E1 links. The E1 cards
have eight ports, with HSSI connections to the routers (75xx).
You can look at the actual throughput under
http://www.switch.ch/lan/stat/linkusa.html
Hope this helps,
We loadshare using Larscom Orion 4000's using 16 x E1's, configured
in a pair of parallel 8 x E1 I-Mux configurations. Behind the
Larsecomm units are cisco routers. The configuration is stable,
and loads evenly over both 16M circuits.
Its not a trans-Pacific STM-1 I admit, but it does the job well and
has done for some two years now.
Geoff Huston
Telstra