Trunking with 3 different Speed connections... Any suggestions?

[Kennygthatsme]

Hi,

From the looks of it I have a fairly rare problem to overcome; I have a split site campus and connecting them is a 10Mbps Motorola P200 Radio link, a 100Mbps MRV Laser Link and a 1Gbps CableFree Microwave Link. All are set to 'Auto' mode on the HP Procurve 2610's I have on either end except the Microwave which has to be forced to 1000FDx as it's Fibre.

I don't currently have Trunking turned on as my setup doesn't meet the requirements (as they’re different speeds) but I do have spanning tree turned on so that, in theory, if one were to drop out the next fastest one would kick in. However, in practice, the Microwave link starts to loose packets when there is heavy rainfall (and living in the south of England provides plenty of that) but the switches don't pick this up as a drop so don't switch to a different link. This wouldn't be a problem if it was a couple of packets, but sometimes it can reach tens of thousands and ping requests time out, so it becomes a real problem for file transfers. Also, the Laser doesn’t like low level sunlight as it is aged and it’s lenses are weakened, but is fine with heavy rainfall, so it would be ideal if I could have them both running at the same time and backing each other up!

I guess, after this fairly long rant, I would just like to hear any suggestions about what you would do if you were in my situation? Obviously Trunking is exactly what I need but with the different speeds my devices run at it's proving a real problem. I thought about putting a Fibre Converter on each end of the Microwave link and truncating it down to 100Mbps so I could trunk it with the Laser, but it would make having a 1Gbps connection pointless, and a lot of money was spent on it so this really isn’t an option.

Any suggestions or scenarios that others use would be greatly appreciated. Thanks for taking the time to read all this!

Many thanks in advance,

Ken

[Shadow13]

What i can understand from what you mentioned that you want to trunk the 3 ports that are connected to different devices to procurve ? if that is what you were saying then you can not do that because the trunk links must be coterminous, means begin together and end together, like this below:

--------
Device 1 -------- Device 2
--------

And cannot be like below:

-------- Device 2
Device 1 -------- Device 3
-------- Device 4

That is wrong and it will not form a trunk.

IF THAT WAS NOT WHAT YOU MENT, please explaing more :D


Regards,
Islam Hassan

Regards,
Islam Hassan

[Kennygthatsme]

Thank you for your response. Sorry if I was unclear, the 3 connections DO all start and end in the same switches, as below:

Site1-----------------------------------Site2
Switch1 -------Radio Link------- Switch2
Switch1 -------Laser Link------- Switch2
Switch1 -----Microwave Link--- Switch2

Both Switch1 and Switch2 are HP 2610's.

The links are the only connection to the other site and therefore must maintain a stable connection between them through rain and shine for them to work as we require them to.

Thanks again,

Ken

[Shadow13]

Thanks for the new data,

You can trunk the links by using hp trunk, hp trunk does not require all ports to be with the same speed, try to trunk the 3 links in 1 trunk group and see if it works, i quote:

" ProCurve does not require all links to be of the same speed and media type when port trunking.
However, it is highly recommended that when port trunking, all links in the same trunk group are configured with the same speed, duplex, and flow control."

If you want you can configure the ports manually to the same speed but by doing that you will not get the best of the higher speed ports.

To configure the TRUNK
use this command:
#trunk trunk

= the ports you want to be trunked together
= Trunk group name (fixed) you kan use any name from trk1 to trk24

USE THIS COMMAND ON BOTH OF THE SWITCHES
after doing that the ports will be removed from any vlans and the trk1 will be the logical name for the 3 links and will be untagged member of vlan 1, so if you want to tag or untage you must use the trk1, the 3 ports will not show separately, they will show as trk1 (grouped together) .

Try that and let me know the results.

Regards,
Islam Hassan

[Pieter 't Hart]

instead of trunking (L2) you may consider load-balanced routing (L3). different speeds are no problem there.
The Gb will be preferred because of its bandwith but packets can be rerouted using the other links.

create two subnets, one for each campus-section.
configure the routing to use both paths
(maybe using a routing protocol like EIGRP).

beware that packets like ping's (udp, broadcast) may be missed but tcp connections will use retransmissions and will behave more resilient.
and though with decreased performance, without data loss.

Pieter

[Shadow13]

EIGRP is Cisco proprietary so it's available only in Cisco devices,the 2nd thing that any other routing protocol will only load balance through equal cost paths so this will not work since the EIGRP is the only protocol that can do load-balancing on unequal cost paths :D.

That's what i know, if my information is not complete or out of date please do tell coz i love to know more :).

[Zeinovich]

Dear Islam;
you can use ospf and change cost to make a load balancing ,,but i think that it will not help
as the drop rate not taken into consideration in ospf so when MW link drop packets due to rains, it will used to fwd packets anyway

[Kennygthatsme]

Thanks for all the comments so far, they are really appreciated.

Thus far I have tried trunking the 11Mbps Radio connection and the 1 Gbps Microwave connection together with some fairly strange results.

Firstly I must explain that the ping times are different for the Microwave and the Radio; If the link is on the Microwave connection then the ping times are <1ms, but if it's on the Radio connection then I will see ping times of from 3ms to 8ms. This, although not an ideal test, tells me which link is currently active when I ping a machine on the other site.

When the trunk is set (to Trunk rather than LACP), I can ping the other site and get the 3ms to 8ms and my colleague can do the same and get the <1ms, which is all well and good as it shows the trunk is doing it's job and spreading the load between the two links. However, when other users on the other site try to connect over the link it seems like the switch is trying to squeeze the majority of them down the Radio link rather than the far more capable Microwave connection, massively slowing bandwidth and causing quite a bottleneck. My worry is that if all 3 connections (including the laser) are set in this configuration, that too many users will be forced down the Radio link making it almost unbearably slow.

Can anyone think of a way around this? Will setting the Trunk to LACP make a difference in this case? Maybe just trunking the 100Mbps Laser and the 1Gbps Microwave will resolve the problem, but then that will render the most reliable device (the Radio) useless.

Any thoughts still greatly appreciated.

Many thanks in advance,

Ken

[Richard Brodie_1]

Off the top of my head, I would set up routing so there is a PINGable address at the far end of every link.

Then I'd run periodic pings from a monitor server, and have it fire off SNMP requests to the switch to route all the main traffic on whatever the fastest link that was behaving adequately. Something like Smokeping might be a start for that.

[Shadow13]

The problem with TRUNK is that it does not load-balance between the links, it only does load-sharing, it uses conversations which is the combination of the source address and the destination address of the packet (SA/DA) and from this info. it then chooses a path randomly and it doesn't care about the speed of the port.

For LACP, it uses the same mechanism, and it requires something more, to configure LACP on ports those ports must be with the same speed to be configured as a trunk group, so in your case you cannot use LACP.

Regards.