Trunk not forming

phoeneous

Two 2950G-12 switches with gigabit gbics installed on ports gi0/1 and gi0/2. I created an etherchannel (Po1) on both switches and added both gi ports to channel group 1. The trunk forms properly and I can hit both switch from either one. So that works.

Now, I setup fa0/10-12 on both switches as trunks. When I connect other switch to the either using any port in the range fa0/10-12, the trunk does not form. I have shut and no shut the interfaces just to make sure. I even configured the fa0/10-12 ports with nonnegotiate to rule out DTP conflicts. This should be pretty straight forward and I'm embarrassed to say that I am stumped. Thoughts?

What I would like to do is configure ports fa0/10-12 on either switch as trunks.

See below for configs.

SWITCH1#sh int trunk
Port        Mode         Encapsulation  Status        Native vlan
Po1         desirable    802.1q         trunking      1
Port      Vlans allowed on trunk
Po1         1-4094
Port        Vlans allowed and active in management domain
Po1         1
Port        Vlans in spanning tree forwarding state and not pruned
Po1         1
SWITCH1#
 
SWITCH1#sh int po1 swi
Name: Po1
Switchport: Enabled
Administrative Mode: dynamic desirable
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
 
SWITCH1#sh int fa0/10 swi
Name: Fa0/10
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: down
Administrative Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
 
---------------------------------------------------
 
SWITCH2#sh int trunk
 
Port        Mode         Encapsulation  Status        Native vlan
Po1         desirable    802.1q         trunking      1
Port      Vlans allowed on trunk
Po1         1-4094
Port        Vlans allowed and active in management domain
Po1         1
Port        Vlans in spanning tree forwarding state and not pruned
Po1         1
 
SWITCH2#sh int po1 swi
Name: Po1
Switchport: Enabled
Administrative Mode: dynamic desirable
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
 
SWITCH2#sh int fa0/10 swi
Name: Fa0/10
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: down
Administrative Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none

mikej412

If you're forming a loop, wouldn't Spanning Tree disable the redundant paths?

phoeneous

mikej412 wrote: »

If you're forming a loop, wouldn't Spanning Tree disable the redundant paths?

And I thought as much but when I disconnect both cables from gi0/1 and gi0/2 from both switches and do a sh int trunk it is just empty. So if I have a single cable from fa0/10 on switch 1 to fa0/10 on witch 2 a trunk never forums. I also tried fa0/11 and fa0/12 on both switches with no luck.

mikej412

Are you using cross-over cables?

peanutnoggin

Are you using crossover cables (not trying to insult your intelligence)? With the GBICs, you should be using fiber (unless you have this copper gbic). The fiber doesn't have a "crossover" because it sends and receives on separate strands. That would explain to me why your fiber is working and not the fast ethernet ports. HTH.

-Peanut

phoeneous

mikej412 wrote: »

Are you using cross-over cables?

Sure am. Tried cat5 and cat6 crossover cables. For the hell of it I even tried straight through.

Peanutnoggin, no offence taken. I am using that 1000 base-t gbic. No fiber.

Even though the switches are using rstp I waited the usual stp times just to make sure the blocked ports werent just transitioning.

networker050184

Can you give us the interface configs? Anything in the logs?

phoeneous

networker050184 wrote: »

Can you give us the interface configs? Anything in the logs?

I'll have to get them tomorrow, it's in our test lab at work.

In the meantime, I labbed it up in packet tracer and I was unable to reproduce the error but at least you guys can see the topology that I am working with.

Basically, on my physical lab, I cannot get a trunk to form from S1 to S3, S4, or S5 and cannot get a trunk to form from S2 to S3, S4, or S5. Originally I thought that 802.1q requires speed and duplex to match but from what I see in packet tracer it doesnt matter. Im going from gigabit ports on S1 and S2 to fast ethernet ports on S3, S4, and S5. I did not hardcode speed or duplex on any of the switches. All cables are crossover.

So to clarify, it seems to work fine in packet tracer but not in my physical lab.

miller811

your show int po1 command should list the interfaces that are configured in the port-channel

try the
Switch# show etherchannel summary

it should list your etherchannel and everything about it.

phoeneous

miller811 wrote: »

your show int po1 command should list the interfaces that are configured in the port-channel

try the
Switch# show etherchannel summary

it should list your etherchannel and everything about it.

And it does, but the problem isnt the etherc trunk not working because the etherc trunk is working. The problem is that the trunks do not for between: S1-S3, S1-S4, S1-S5, S2-S3, S2-S4, S2-S5.

Heero

how about some configs....

Akiii

please do the 2 sh runs

phoeneous

See below for configs. All I'm trying to do is trunk between fa0/12 on S1 to gi0/1 on S3. Gi0/1 on S3 is a 1000 Base-T gbic if that matters. The etherchannel is irrelevant at this point.

S1:

S1#sh run
Building configuration...
Current configuration : 2377 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname S1
!
enable secret 5 snip
!
username root privilege 15 password 7 snipsnip
ip subnet-zero
!
ip domain-name snip
ip name-server snip
ip ssh time-out 120
ip ssh authentication-retries 3
ip ssh version 2
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface Port-channel1
!
interface FastEthernet0/1
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/2
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/3
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/4
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/5
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/6
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/7
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/8
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/9
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/10
 switchport mode trunk
 switchport nonegotiate
!
interface FastEthernet0/11
 switchport mode trunk
 switchport nonegotiate
!
interface FastEthernet0/12
 switchport mode trunk
!
interface GigabitEthernet0/1
 channel-group 1 mode on
!
interface GigabitEthernet0/2
 channel-group 1 mode on
!
interface Vlan1
 ip address snip 255.255.255.0
 no ip route-cache
!
ip default-gateway snip
no ip http server
!
line con 0
 password 7 snip
 logging synchronous
 login
line vty 0 4
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
line vty 5 15
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
!
ntp server snip
!
end

S3:

S3#sh run
Building configuration...
Current configuration : 6283 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname S3
!
enable secret 5 snip
!
username root privilege 15 password 7 snipsnip
ip subnet-zero
!
ip domain-name snip
ip name-server snip
ip ssh time-out 120
ip ssh authentication-retries 3
ip ssh version 2
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface FastEthernet0/1
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
<INTERFACES FA0/2-47 SNIPPED>
!
interface FastEthernet0/48
 switchport mode trunk
!
interface GigabitEthernet0/1
 switchport mode trunk
!
interface GigabitEthernet0/2
 switchport mode trunk
 switchport nonegotiate
!
interface Vlan1
 ip address snip 255.255.255.0
 no ip route-cache
!
no ip http server
!
line con 0
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login
line vty 0 4
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
line vty 5 15
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
!
ntp server snip
!
end

Monkerz

Set the interfaces to 100/Full.

Akiii

phoeneous wrote: »

See below for configs. All I'm trying to do is trunk between fa0/12 on S1 to gi0/1 on S3. Gi0/1 on S3 is a 1000 Base-T gbic if that matters. The etherchannel is irrelevant at this point.

S1:

S1#sh run
Building configuration...
Current configuration : 2377 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname S1
!
enable secret 5 snip
!
username root privilege 15 password 7 snipsnip
ip subnet-zero
!
ip domain-name snip
ip name-server snip
ip ssh time-out 120
ip ssh authentication-retries 3
ip ssh version 2
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface Port-channel1
!
interface FastEthernet0/1
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/2
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/3
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/4
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/5
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/6
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/7
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/8
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/9
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
interface FastEthernet0/10
 switchport mode trunk
 switchport nonegotiate
!
interface FastEthernet0/11
 switchport mode trunk
 switchport nonegotiate
!
interface FastEthernet0/12
 switchport mode trunk
!
interface GigabitEthernet0/1
 channel-group 1 mode on
!
interface GigabitEthernet0/2
 channel-group 1 mode on
!
interface Vlan1
 ip address snip 255.255.255.0
 no ip route-cache
!
ip default-gateway snip
no ip http server
!
line con 0
 password 7 snip
 logging synchronous
 login
line vty 0 4
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
line vty 5 15
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
!
ntp server snip
!
end

S3:

S3#sh run
Building configuration...
Current configuration : 6283 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname S3
!
enable secret 5 snip
!
username root privilege 15 password 7 snipsnip
ip subnet-zero
!
ip domain-name snip
ip name-server snip
ip ssh time-out 120
ip ssh authentication-retries 3
ip ssh version 2
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface FastEthernet0/1
 switchport mode access
 spanning-tree portfast
 spanning-tree bpduguard enable
!
<INTERFACES FA0/2-47 SNIPPED>
!
interface FastEthernet0/48
 switchport mode trunk
!
interface GigabitEthernet0/1
 switchport mode trunk
!
interface GigabitEthernet0/2
 switchport mode trunk
 switchport nonegotiate
!
interface Vlan1
 ip address snip 255.255.255.0
 no ip route-cache
!
no ip http server
!
line con 0
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login
line vty 0 4
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
line vty 5 15
 exec-timeout 0 0
 password 7 snip
 logging synchronous
 login local
 transport input telnet ssh
!
ntp server snip
!
end

Try to hardcode the speed and duplexity or to auto on both sides in your lab as see what happens.

And how do you mean that the trunk is not forming? What's the status of the ports when you say that they are not "forming"?

phoeneous

Akiii wrote: »

Try to hardcode the speed and duplexity or to auto on both sides in your lab as see what happens.

And how do you mean that the trunk is not forming? What's the status of the ports when you say that they are not "forming"?

It is not letting me set speed or duplex on the gbic ports. The ports on either switches are down down.

Panzer919

Correct me if I'm wrong but trunks usually indicate multiple vlans traversing. Would it not form because only one vlan is specified? So the ports are just acting as access ports since there is only 1 vlan.

Are the ports showing up/up if you do a show int fa0/x?\

Also the GBIC ports are probably 1000/full only so you wouldnt be able to set them. what about the Ethernet ports?

phoeneous

Panzer919 wrote: »

Correct me if I'm wrong but trunks usually indicate multiple vlans traversing. Would it not form because only one vlan is specified? So the ports are just acting as access ports since there is only 1 vlan.

Are the ports showing up/up if you do a show int fa0/x?\

Also the GBIC ports are probably 1000/full only so you wouldnt be able to set them. what about the Ethernet ports?

I've set the ports as trunks, I dont think the number of vlans matters but I could be wrong. The fa and gi ports show as down down. Now if I trunk from fa port to fa port then everything is fine. The issue seems to be going from fa port to gi/gbic port.

Panzer919

if you are going from a gig port to a fa port switch everything to the same link types and see if it comes up.

gig to gig should form a trunk and fa to fa should at least come up/up. Since im almost certain that most GBICS were pretty much hard coded to the max transmission speed they will probably not work with a regular port that cannot go 1000/full

phoeneous

Panzer919 wrote: »

switch everything to the same link types

Do you mean speed and duplex?

Panzer919

meaning fastethernet ports should connect to fastethernet ports and GBICs should connect to GBIC's

VAHokie56

phoeneous wrote: »

I've set the ports as trunks, I dont think the number of vlans matters but I could be wrong. The fa and gi ports show as down down. Now if I trunk from fa port to fa port then everything is fine. The issue seems to be going from fa port to gi/gbic port.

You should be able to set the speed on the gig port , what version ios are you using ?

Monkerz

If you are using a 1000 only GBIC, you will never be able to form a trunk with a fastethernet port. If your GBIC was 10/100/1000 you could set it to 100/Full and set the Fast Ethernet port 100/Full and the trunk would come up. The speeds must match. So you have figured out your problem.

Panzer919

Monkerz wrote: »

If you are using a 1000 only GBIC, you will never be able to form a trunk with a fastethernet port

These are the GBIC's I am used to and when he said that he could not change the speed/duplex I knew it was one of these. I know there are GBIC's that can be 10/100/1000 but in my experience at least, the companies I delt with all purchased the 1000 only GBIC's because they being used for were HCC's or VCC's.

Monkerz

Panzer919 wrote: »

These are the GBIC's I am used to and when he said that he could not change the speed/duplex I knew it was one of these. I know there are GBIC's that can be 10/100/1000 but in my experience at least, the companies I delt with all purchased the 1000 only GBIC's because they being used for were HCC's or VCC's.

I understand, we purchase Dell and Cisco GBICs. The Dell ones are hardcoded at 1000, the Cisco allows 100/1000.

phoeneous

VAHokie56 wrote: »

You should be able to set the speed on the gig port , what version ios are you using ?

c2950-i6k2l2q4-mz.121-22.EA14.bin

The only s? commands are:

service-policy
shutdown
snmp
spanning-tree
storm-control
switchport

phoeneous

Monkerz wrote: »

I understand, we purchase Dell and Cisco GBICs. The Dell ones are hardcoded at 1000, the Cisco allows 100/1000.

What's the part number for the 100/1000 gbic? The ones I have are WS-G5483.

Cisco Gigabit Interface Converter [Cisco GBICs] - Cisco Systems

Panzer919

those are gig only GBIC's

phoeneous

Panzer919 wrote: »

those are gig only GBIC's

I know. What I'd like to know is the part number for 100/1000 gbics.

I've decided to scrap the original idea that I had for this based on our findings. Thanks for everyones help on this.