[c-nsp] 7200 - G1 PortChan MTU

[CiscoNSP List]

Both phys-ints are showing 1500byte mtu, as is portchan

#sh int gigabitEthernet 0/1
GigabitEthernet0/1 is up, line protocol is up 
  Hardware is BCM1250 Internal MAC, address is 00d0.bc5b.bc1b (bia 00d0.bc5b.bc1b)
  Description: GEC_TO_CSW01_24
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, 
     reliability 255/255, txload 6/255, rxload 5/255

#sh int gigabitEthernet 0/3
GigabitEthernet0/3 is down, line protocol is down 
  Hardware is BCM1250 Internal MAC, address is 00d0.bc5b.bc1b (bia 00d0.bc5b.bc19)
  Description: GEC_TO_CSW02_24
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, 
     reliability 254/255, txload 1/255, rxload 1/255

#sh int port-channel 1
Port-channel1 is up, line protocol is up 
  Hardware is GEChannel, address is 00d0.bc5b.bc1b (bia 00d0.bc5b.bc1b)
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, 
     reliability 255/255, txload 10/255, rxload 5/255


Phys-int conf:

interface GigabitEthernet0/1
 description GEC_TO_CSW01_24
 mtu 1998
 no ip address
 ip mtu 1998
 ip flow ingress
 duplex auto
 speed auto
 media-type rj45
 no negotiation auto
 channel-group 1
end

And portchan1:

interface Port-channel1 no ip address
 ip access-group 103 in
 ip flow ingress
 load-interval 30
 duplex full
end




Date: Sat, 20 Jul 2013 20:42:39 -0700
From: randy_94108 at yahoo.com
Subject: Re: [c-nsp] 7200 - G1 PortChan MTU
To: cisconsp_list at hotmail.com; cisco-nsp at puck.nether.net

what is the output fo sh int for phy-ints and sho int po(x)

        From: CiscoNSP List <cisconsp_list at hotmail.com>
 To: "randy_94108 at yahoo.com" <randy_94108 at yahoo.com>; "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net> 
 Sent: Saturday, July 20, 2013 8:22 PM
 Subject: RE: [c-nsp] 7200 - G1 PortChan MTU
   





Both member Ints have the same conf (i.e. both have mtu of 1998) - It's only the portchan that doesnt have an mtu set (So is defaulting to 1500)?




> Date: Sat, 20 Jul 2013 19:42:31 -0700
> From: randy_94108 at yahoo.com
> Subject: Re: [c-nsp] 7200 - G1 PortChan MTU
> To: cisconsp_list at hotmail.com; cisco-nsp at puck.nether.net
> 
> it doesn't matter that the second phyical-member of this port channel is disconnected. It is still a member of this bundle. UP mtu of inactive phy-member to 1998 and then up mtu of port-channel.
> ./Randy
> 
> 
> 
> ----- Original Message -----
> > From: CiscoNSP List <cisconsp_list at hotmail.com>
> > To: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
> > Cc: 
> > Sent: Saturday, July 20, 2013 7:20 PM
> > Subject:
 [c-nsp] 7200 - G1 PortChan MTU
> > 
> > Hi,
> > 
> > Have a G1, with one active Gig port in a portchan (Second member is currently 
> > disconnected, but is also a Gig port on the G1) - No other ports are configured 
> > as member ports.
> > 
> > Gi0/1 (Active member) has an mtu of 1998 - Portchan doesnt have an mtu 
> > configured (So is defaulting to 1500)
> > 
> > Attempting to change the mtu on the portchan, I get the following:
> > 
> > (config)#interface Port-channel1(config-if)#mtu 1998               % At least 
> > one member of the channel group 1 is not a 2FE port adapter
> > 
> > Any suggestions why this is happening? 
> > 
> > And I assume the only way to resolve this is to default the member ints, re-add 
> > them to the portchan and then
 change the mtu on the portchan?
> > 
> > Cheers.
> > 
> > 
> >                           
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> >