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Distinguished Expert
Distinguished Expert
pk
Posts: 824
Registered: ‎10-09-2008
0
Accepted Solution

Autonegotiation on MX-80

Hi All

 

Should be a stupid question, but I'm confused with the way autonegotiation works in Junos. On one side (mxA-1), I have

 

ge-1/1/2 {
    unit 0 {
        family inet {
            address 172.18.112.1/30;
        }
    }
}

 

while on the other (mxA-2),

 

ge-1/1/2 {
    speed 10m;
    unit 0 {
        family inet {
            address 172.18.112.2/30;
        }
    }
}

 

On both sides, autonegotiation is enabled,

 

lab@mxA-1> show interfaces ge-1/1/2 detail | match Auto 
  Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, Remote fault: Online

lab@mxA-2> show interfaces ge-1/1/2 detail | match Auto   
  Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, Remote fault: Online

 

But the link is down. It goes up if I delete "10m" setting from one side or put "10m" also on the other. The devices are MX80's with Juniper SFP-T and Junos 11.2R6.3 but it does not seem to depend on version.

 

I do not understand why autonegotiation is in fact not working. Is it by design?

Best Regards,
Petr (PK)

Juniper Ambassador, Juniper Networks Certified Instructor,
JNCIE-SEC #98, JNCIE-ENT #393, JNCIE-SP #2253
[Juniper Authorized Education & Support in Russia]
Visitor
tgoncalves
Posts: 7
Registered: ‎06-28-2012
0

Re: Autonegotiation on MX-80

Hi PK,

 

Despite this link is on Cisco website, I think it will clarify your doubts about Autonegotiation.

 

 

Troubleshooting Cisco Catalyst Switches to NIC Compatibility Issues

http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a00800a7af0.shtml

 

Distinguished Expert
Distinguished Expert
pk
Posts: 824
Registered: ‎10-09-2008
0

Re: Autonegotiation on MX-80

Hi tgoncalves,

 

Thanks for your reply. However, from Table 1 of your link it follows that if I have 10M on one side and AUTO on the other, then link is established at 10M, which I would also expect, but the problem is that I don't see it.

 

So my original question remains.

 

Best Regards,
Petr (PK)

Juniper Ambassador, Juniper Networks Certified Instructor,
JNCIE-SEC #98, JNCIE-ENT #393, JNCIE-SP #2253
[Juniper Authorized Education & Support in Russia]
Trusted Expert
Trusted Expert
jtb
Posts: 314
Registered: ‎08-26-2009

Re: Autonegotiation on MX-80

hi,

 

just a hint:  is it  SFP-1GE-T or SFP-1GE-FE-E-T ? Based on http://www.juniper.net/techpubs/en_US/release-independent/junos/topics/reference/general/dpc-mx-seri...

 

  • 1000BASE-T (model number: SFP-1GE-T)
  • 10/100/1000BASE-T (model number: SFP-1GE-FE-E-T)

Note: SFP-1GE-FE-E-T supports tri-rate 10/100/1000 mode in Junos OS Release 9.4 and later

jtb

 


Distinguished Expert
Distinguished Expert
pk
Posts: 824
Registered: ‎10-09-2008
0

Re: Autonegotiation on MX-80

Hi jtb,

 

It is SFP-1GE-T. But with "speed 10m" on both ends, the link works.

 

I also tried with EX switches (not SFP, just 10/100/1000 ports), and there autonegotiation works as expected (speed 10m on one side and AUTO on the other => link up at 10m).

 

So I think you are right and the problem is in SFP here. I will mark it as a solution but kudos to anyone who can shed some more light on this.

Best Regards,
Petr (PK)

Juniper Ambassador, Juniper Networks Certified Instructor,
JNCIE-SEC #98, JNCIE-ENT #393, JNCIE-SP #2253
[Juniper Authorized Education & Support in Russia]
Super Contributor
ChadM
Posts: 175
Registered: ‎10-14-2008
0

Re: Autonegotiation on MX-80

Since going between switches are you using a crossover cable or straight through cable?  I've seen some hardware where manually setting speed would disable auto-mdix.  It's possible this is a bug.

 

There was also a config requirement at some point to explicitly disable auto-negotiation when setting speed manually.  Leaving it enabled, the default, would cause the interface to not come up.

 

set interfaces ge-x/y/z speed 100m
set interfaces ge-x/y/z link-mode full-duplex
set interfaces ge-x/y/z gigether-options no-auto-negotiation

 

-Chad

 

Visitor
Johnson P Liu
Posts: 2
Registered: ‎01-22-2013
0

SFP-1GE-T vs SFP-1GE-FE-E-T

Dear all:

  Is anyone can tell me how to differentiate the two SFP ?

Because I cannot tell by it outlook (same part number) and show chassis hardware command (all called SFP-T), the only difference I can tell is S/N C072XXX was my new purchase SFP(SFP-1GE-FE-E-T), others are old SFP-1GE-T

 

Xcvr 0 REV 02 740-013111 C072022 SFP-T
Xcvr 1 REV 01 740-013111 8166763 SFP-T
Xcvr 2 REV 02 740-013111 C072184 SFP-T
Xcvr 3 REV 01 740-013111 8166669 SFP-T
Xcvr 5 REV 02 740-013111 C072779 SFP-T


Xcvr 4 REV 02 740-013111 C072852 SFP-T
Xcvr 5 REV 02 740-013111 C072308 SFP-T
Xcvr 6 REV 02 740-013111 C072744 SFP-T
Xcvr 7 REV 01 740-013111 8166732 SFP-T

Contributor
mdheavy
Posts: 14
Registered: ‎09-03-2012
0

Re: Autonegotiation on MX-80

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