Ethernet Switching
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New User
mxyoung
Posts: 5
Registered: ‎01-10-2009
0

Gigabit Ethernet (SX fiber) to Cisco 3550

I can't seem to link my EX 4200s to a Cisco 3550. Link comes up fine between Cisco and a 3Com 4500 (the switch I'm replacing with the EX 4200), but I get no link lights when plugged into the 4200 (but link is up\up on the Cisco).

 

Cisco is set to 1000Mb\full duplex (not auto). Tried lots of combinations on the Juniper, replaced SX Gbic with known good Gbic. I want to have the Juniper port in Routing Uplink mode, but changing the mode doesn't change anything. Just up\up on the Cisco and up\down on the Juniper.

 

Ideas?

Distinguished Expert
firewall72
Posts: 825
Registered: ‎05-04-2008
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

Hi,

 

Would you mind posting your port config?

 

-John

John Judge
JNCIS-SEC, JNCIS-ENT,

If this solves your problem, please mark this post as "Accepted Solution". Kudos are appreciated.
New User
mxyoung
Posts: 5
Registered: ‎01-10-2009
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

Very basic:

 

    ge-0/1/3 {
        apply-macro juniper-port-profile {
            "Routed Uplink";
        }
        description Cogent;
        mtu 2000;
        ether-options {
            no-auto-negotiation;
            no-flow-control;
            link-mode full-duplex;
            speed {
                1g;
            }
        }
        unit 0 {
            family inet {
                address X.X.X.X/30;
            }
        }
    }

 

I  have tried all kinds of options on this. On the 3Com, my config is simply "speed 1000M, duplex full" and the port comes up. It does not come up when autonegotiating on the 3Com. The Cisco is owned by my provider, I've asked them to paste the port config into an email and send it to me... but haven't gotten it. Since it comes up on the 3Com with just the basic speed and port settings, I don't think there is anything fancy involved.

Contributor
a_2X4
Posts: 47
Registered: ‎10-23-2008
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

I am having problems with connecting the EX series to Cisco 3550s also. My situation presents differently since both ends show up/up.The problem I am running into is a VLAN inconsistency reported by the 3550, even if switched through a 3560 first. Problem presents only with the Cisco 3550. Work-around was to disable spanning-tree on the VLAN on the 3550.

Point is, try a different switch if possible to see if the error remains.

 

I do remember having a problem that presented with the lights as you are discribing it. As best I recall, it was a speed/duplex issue. Issue the "no negotiate" command on the 3550s uplink port, if it supports it; and set "switchport mode access".

With a 3750G-12S, I had to set the EX to "set speed 1g", but leave the Cisco to default. If you want to trunk, you have to set the Cisco to dot1q.

New User
mxyoung
Posts: 5
Registered: ‎01-10-2009
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

Thanks for the info and experience. The only problem I have is, I don't have access to the Cisco. I'm buying an Ethernet circuit from Cogent, and it is their Cisco. So the only thing I can change is the Juniper :-(
Contributor
a_2X4
Posts: 47
Registered: ‎10-23-2008
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

MPLS ?

Congent needs to put in a better device; not something that you can control.

 

They probably have you segmented using a VLAN; whether they tell you or not. Since the Juniper is not routing, it should not matter; the family inet should handle everything there.

 

I'm guessing that the Congent tech is telling you that the 3550 is up/down. Will s/he give you a copy of the running-config, even if it is just the config for your port on it? Make sure that it is set to "switchport mode access"

 

I have a building with about thirty 3550s plugged into an EX VC. Not problem-free, but they are all up/up right now. Mine are all L2 configs; whereas, you have L3 setup.

 

The biggest issue I have is with VLAN propergation. The Cisco does it's propietary PVST and auto-negoiate everything expecting to be connected to another like-Cisco device.

Most up/down issues have been with spanning-tree blocking. There is also the access/trunk problem blocking.

Ask the tech to do a "show spanning-tree summary" just to eliminate the possiblity.

 

This is probably going to be one for J-TAC or your local Juniper Engineer.

 

 

New User
mxyoung
Posts: 5
Registered: ‎01-10-2009
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

The Cogent side is up/up -- otherwise, I agree with most everything there. I am trying to pull some details out of them. I did open a JTAC issue.
Visitor
mmainer
Posts: 9
Registered: ‎01-29-2008
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

[ Edited ]

Can you loop your interface with a single fiber?  You know TX <-> RX and does you Int come up?  Have you tried removing the "  no-auto-negotiation" command from your int?

 

Besides this the only other thing is to ensure you both have SX optics and MM fibers, I have seen this many times where the order is written for SX but the product is installed on SM fibers.

Message Edited by mmainer on 01-22-2009 05:54 AM
-Mike Mainer
New User
mxyoung
Posts: 5
Registered: ‎01-10-2009
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

Yes, did all that. I can even take that Juniper GBIC and plug it into the 3Com mini gbic slot and get the connection up immediately.

 

I did get a little more info on the Cisco config. Here is the port config on that side:

 

no switchport

ip address X.X.X.X 255.255.255.252

no ip redirects

no ip proxy-arp

speed nonegotiate

flowcontrol send off

no cdp enable

 

pretty simple....  but I can't change anything on that side, only on the Juniper 4200.

Trusted Contributor
SapphireNET
Posts: 154
Registered: ‎03-27-2008
0

Re: Gigabit Ethernet (SX fiber) to Cisco 3550

[ Edited ]

the issue is with the auto-negotiation.

 

If they remove the cisco side "speed no-neogitate" your link will come up.

 

I had this issue and it doesnt matter what you put under your ether-options until the cisco command is removed no joy!

 

I opened a case with JTAC and they have confirmed that the is an open PR for this issue.

 

Note, this was also with Cogent, and they told me that unless the ports are no-negotiate  their SLA is not applied.

Message Edited by SapphireNET on 01-23-2009 04:37 PM
JNCIS-M, JNCIS-SEC
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