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dughutch
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How does one properly utilize MME with external links?

Sat Apr 24, 2010 5:12 pm

We are trying to make use of many 450G's and external links to create a layer 3 mesh and are having NO success. (The purposes of our meshing are mobility and redundancy.) Please help us understand how to properly configure MME to enable this solution. (Yes, we have carefully studied the 2 wiki topics to no avail.) (In the final solution the wired ethernet will be replaced with external radio links.)

On our test bench we configured three 450G's to use MME. Each 450G had eth1 configured as an IP in a class C. Eth2, eth3, eth4, and eth5 were each configured with independent, separate, unique class C subnets. Eth2, eth3, eth4, and eth5 were added as MME interfaces. The eth1 Class C was added as a network into MME.

The test bed topology was as follows. All eth2 interfaces were connected to a unique dumb switch. All eth3 interfaces were connected to a different unique dumb switch. All eth4 interfaces were connected to yet another different unique dumb switch. All eth5 interfaces were connected to yet another separate unique dumb switch.

Eth1 on a 450G was connected directly to a laptop with an IP in its respective class C and the laptop was connected to the 450G with Winbox. Eth1 on a 450G was connected directly to another unique laptop with an IP in its respective class C and the laptop was connected to the 450G with Winbox.

The routing tables on both 450G's (displayed via Winbox) showed that the 450G's had learned about the class C network on eth1 on the opposite 450G. At this point one laptop was able to ping the other. :)

Next we unplugged eth2 from one of the 450G's and pings stopped. :( For three pings "request timed out" was displayed and then "destination unreachable" was displayed. We were expecting that traffic would be transmitted over either: eth3, eth4 or eth5 which were still directly connected to the dumb switches or that the traffic would be routed via the other 450G which was also connected.

After one minute pings did resume and were traveling direct from the first 450G to the second 450G via eth3. (The MME hold down timer was set to 1 minute).

An additional thing we noticed on the interfaces while MME was running was that there was no dynamic IPIP interface as the wiki explained there should be. This leads us to believe either we are doing something wrong or MME is not functioning correctly. We are using RouterOS 4.7 (the latest stable at this time).

Please help!
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Last edited by dughutch on Tue May 18, 2010 4:57 pm, edited 2 times in total.
 
dughutch
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Re: How does one properly utilize MME with external links?

Sat May 01, 2010 9:10 pm

Bump
 
gregsowell
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Re: How does one properly utilize MME with external links?

Tue May 18, 2010 5:35 am

Douglas,

So you are doing mesh on your interfaces (red, green, yellow, grey). What subnets are you running on these interfaces? Are you doing static routing or OSPF?

What subnets do you have running on the two laptops? Are you bridging those blue interfaces, or routing them?
 
rojwilco
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Re: How does one properly utilize MME with external links?

Tue May 18, 2010 4:15 pm

Gregsowell,

I was working with Doug on the same setup. We were not using "Mesh" (as its called in RouterOS), but rather the MME routing protocol. Each colored segment in the drawing is its own subnet, and each interface had an IP in this subnet. There was no other routing configured on the box other than MME, since that is how the documentation explained how to set it up.
 
dughutch
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Re: How does one properly utilize MME with external links?

Tue May 18, 2010 4:46 pm

Additional information from forum post: http://forum.mikrotik.com/viewtopic.php?f=14&t=41190
Thank you. Alas, we have read both the pages on the wiki that you site but are unable to get MME working. Perhaps we are doing something completely wrong. Our example is illustrated in the following post.

Maybe we are not understanding how the protocol works? We were expecting "seemless" failover with no loss... instead it took one minute... the same as the hold down timer... as we are working with a rapidly changing topology (not accurately depicted in picture) perhaps our settings should be:

origination-interval = 1s

timeout = 2s

This might lead us to only have a 2 second loss... still not ideal... but a great improvement.

Thoughts?
 
dughutch
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Re: How does one properly utilize MME with external links?

Tue May 18, 2010 4:51 pm

Douglas,

So you are doing mesh on your interfaces (red, green, yellow, grey). What subnets are you running on these interfaces? Are you doing static routing or OSPF?

What subnets do you have running on the two laptops? Are you bridging those blue interfaces, or routing them?
Subnets on interfaces:
Red: 172.16.1.x/24
Green: 172.16.2.x/24
Yellow: 172.16.3.x/24
Grey: 172.16.4.x/24

No routing other than MME

Laptop Alpha 10.0.1.x/24
Laptop Bravo 10.0.2.x/24

Blue interfaces (eth1) routed (MME).