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Layer 2 Etherchannel different carriers

Louis Adams
Level 1
Level 1

Hi,

I have 2 metro ethernet Layer 2 circuits by 2 different carriers.  They fully pass all vlan traffic.  When I do a show cdp neighbor command I see the switch on the other side.  My question is, is it possible to etherchannel 2 ports over different carries.  physically the 2 ports are not connected to each other just logically.

29 Replies 29

bear in mind that if you using provider network, the interface never go down - because your switch port is connected to NTU - this interface always up. (and far go down, you will not notice)

 

you need to crack with CDP neighbour also an advanced level, just my thought. or create Local VLAN for a different provider. and track them is a good idea. rather rely on hardware interface.

 

Another case if have access both the side, you can control with IGP. (ex: OSPF)

 

 

 

BB

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How to Ask The Cisco Community for Help

as i told balaji, the exemple was to open his mind.. and i suggested to him use a ip sla to get a better information and a better control of it.
Jaderson Pessoa
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Yeah man, the exemple was to open your mid the many possibility that you can do with it.. Using IPSLA to get information about network directly connected in each ISP for each site that you want monitor.. it certainly will help you with your issue.
Jaderson Pessoa
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Thanks for everyones input.  I have gotten most of it figured out, the problem now is I am not sure how set my threshold on the ip sla.  Here is the current config

 

track 1 ip sla 1 reachability
delay down 45 up 60

 

ip sla 1
icmp-echo 10.0.0.1 source-interface Vlan1
ip sla schedule 1 life forever start-time now
ip sla reaction-configuration 1 react timeout threshold-type consecutive 16
ip sla enable reaction-alerts

 

I am trying to allow for some time before issuing the shutdown port commands.  I have tried variuos things.  So for example if it does not get a response from 10.0.0.1 x number of seconds then alert.  Should I use RTT instead?  Hope this makes sense.  

 

 

ip sla 10
icmp-echo 10.0.0.1 source-ip source-interface Vlan1
threshold 400

 

just it will solve your problem...  if threshold is over 400ms, it will be considered down. :)

 

 

 

Jaderson Pessoa
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So is there a way to tell it not to alert unless 10.0.0.1 is unreachable for at least 1 minute? or is 60 seconds.  I see I can set a time out value as well.  Not quite sure the difference.

what I am trying to accomplish is if the link is down for just a couple of minutes, I don't want the ports being shutdown etc.  

Here is what I am attempting to see if it works

 

ip sla 1
icmp-echo 10.0.0.1 source-interface Vlan1
frequency 180000
timeout 121000
threshold 60000
ip sla schedule 1 life forever start-time now
ip sla reaction-configuration 1 react timeout threshold-type immediate
ip sla enable reaction-alerts

 

correction on the frequency 180 (that is in seconds not milli LOL)

 

As I was reading through the first few responses I was going to mention this but see you figured it out.  You can do port channel using two separate service provider layer 2 links.  we did it until we ran into this black holing issue.  We then moved to doing OSPF with load balancing instead which has worked out great.

Larry,

I have limited knowledge of OSPF, but I do no it is a routing protocol.  this is layer 2 with some of the same vlans on each side, how do you use OSPF to do load balancing with out creating loop?

you can create a vlan and limit trough switchport trunk allowed vlan.. and each vlan will monitor a link that will be "directly connected" for each link... so in this case you wont have routing loop :)
Jaderson Pessoa
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In our case our Layer2 WAN services terminated on an ASR.  We did layer 3 port-channel.  Once we ran into the black holing,  I suggested OSPF and we moved to that successfully.  If your WAN services terminate on a layer 2 only device then implementing OSPF will be that much more intrusive to get running.  That being said, if you do OSPF load balancing across two circuits then of course you have to do routing instead of switching (which sounds like your biggest concern.)  If these are the only two circuits between sites then no worries about a loop as OSPF has measures to protect against that.

Jaderson,

 

Went a head and accepted this as a solution, since it is just a matter of fine tuning etc.  At this point it switched to IP SLA configuration etc.


Thanks for your help.

Thank you Luis, if you need any assistance let we know. :)
Jaderson Pessoa
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