Trunking Question between 2801 & 2950

[sk391]

Hello All, im studing for my CCNA and am setting up a home lab. I have a question about inter vlan routing, I have two 2950 switches and have a trunk set up between then using encapsulation protocol dot1q everthing is ok. Now I want to connect a crossover cable from another port on on my switches ( leaving the existing trunk in place) to a router 2801. I have connected it to the fa 0/0 port on the 2801 and trying to set up a router on a stick config. The problem Im having looks like the trunk between the 2950 switch and the 2801 on router will not come up. I have config'ed subinterfaces on the router using the following commands:

config t
int fa 0/0.10
encapsulation dot1q 10
ip address 192.168.0.1 255.255.255.0
no shutdown

but the port on the switch will not light up.

I have put a switchport mode trunk command on the switch but when I enter in a show int trunk command it doesnt list my port as a trunk only the other existing port the one which connects the two 2950 together.

Can anyone point me in the right direction please.

p.s If I get a staightthrough cable and connect int f 0/0 to the 2950 the ports light up and it says port a line protocols are up.

Thanks

 

[Alterac]

Does it not work with the straigh thru cable?

If you dont get link with xover, but you do with the straight, then use the straigh cable.



----------------------------------
Bill

 

[sk391]

Thanks - its always the simplist answer that works. before the orginial post I used a straight through saw the interface light up, but I thought that it wasnt right because to trunk between switches you have to have a x-over and I through it would be the same for a link between a switch and router, but it looks like it doesnt work with x-over but does with a straight-through.

Thanks, the link is up now ... panic over... until next time

 

[jneiberger]

Crossover cables are for switch-to-switch connections (or PC to PC, for example). You use a straight cable to connect end devices (like PCs or routers) to switches.

It has nothing to do with trunking. It's all about which pins electrically carry which signals. Your ins and outs have to match up.

 

[burtsbees]

I thought you can connect a straight for trunk connections, and a crossover for an uplink (to extend the switch, per se)...

Burt

 

[sk391]

Guys Im still struggleing with this config. I been over it a few times and believe that I have the theory and command sorted but just will not work.

config from the switch....

interface FastEthernet0/0
no ip address
no ip route-cache
speed 100
full-duplex
no mop enabled
!
interface FastEthernet0/0.10
encapsulation dot1Q 10
ip address 172.12.2.1 255.255.255.0
no ip route-cache
no snmp trap link-status
!
interface FastEthernet0/0.20
encapsulation dot1Q 20
ip address 172.12.4.1 255.255.255.0
no ip route-cache
no snmp trap link-status
!
interface FastEthernet0/1
ip address 10.1.1.3 255.0.0.0
no ip route-cache
duplex auto
speed auto
!
interface Serial0/3/0
no ip address
no ip route-cache


config from the switch (2950 )

SwitchB>show vlan brief

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/4, Fa0/5
Fa0/6, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/11, Fa0/12, Fa0/13
Fa0/14, Fa0/16, Fa0/17, Fa0/18
Fa0/20, Fa0/21, Fa0/22, Fa0/24
10 accounts active Fa0/19
12 Testvlan active
20 hr active Fa0/15
50 ITdepartment active
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup




Fa0/3 on 802.1q trunking 1
Fa0/23 desirable 802.1q trunking 1

Port Vlans allowed on trunk
Fa0/3 1-4094
Fa0/23 1-4094

Port Vlans allowed and active in management domain
Fa0/3 1,10,12,20,50
Fa0/23 1,10,12,20,50

Port Vlans in spanning tree forwarding state and not pruned
Fa0/3 1,10,12,20,50
Fa0/23 1,10,12,20,50


ip address pc 1 connected to vlan 10 is 172.12.2.2 /24
deafualt gateway 172.12.2.1

ip address pc 2 connected to vlan 20 is 172.12.4.4 /24
default ip gateway 172.12.4.1

this should work? from a pc I can ping the subinterface on the router for it ip subnet and the other subinterface for the other vlan ie from pc 1 i can ping 172.12.2.1 & 172.12.4.1 but not the actual hosts. There is no firewall on.

Any ideas???/

 

[ComputerKid1988]

Thanks - its always the simplist answer that works. before the orginial post I used a straight through saw the interface light up, but I thought that it wasnt right because to trunk between switches you have to have a x-over and I through it would be the same for a link between a switch and router, but it looks like it doesnt work with x-over but does with a straight-through.

Thanks, the link is up now ... panic over... until next time"

Looks like someone didn't pay attition in Cisco 1

 

[Alterac]

can you post a full sh run (sanatized, without passwords) for the router?

Everything looks good, it just seems somthing is blocking the traffic, maybe your not routing on the router?



----------------------------------
Bill

 

[burtsbees]

What ports are pc1 and pc2 connected to? Post a sh run of these ports only, I.E. if pc1 is connected to fa0/5 of the switch, then post "sh run int fa0/5", and same for the port that pc2 is physically connected to.
Actually, post a sh run from the switch and indicate which ports the pcs are physically connected to. If they are fa0/3 and fa0/23, that's wrong---they should be access ports, not trunks. The only trunk port you should have is the one physically connected to the router...please indicate what physical port that is as well.

Burt

 

[Alterac]

That right, I didnt see that.

Clients should be hooked up to Access ports, not Trunk ports.

Thanks Burt

----------------------------------
Bill

 

[burtsbees]

Sure---most times trunking and intervlan routing is done through L3 switches these days, not RoaS...easy to forget all the specifics...

Burt

 

[sk391]

thanks guys... I have posted the config of the switch.

Port 3 is connected to the router
port 24 is trunking to another 2950 switch

ip ssh time-out 120
ip ssh authentication-retries 3
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!

The hosts are connected on port 15 & 19


!
interface FastEthernet0/1
!
interface FastEthernet0/2
switchport mode access
speed 100
!
interface FastEthernet0/3
switchport mode trunk
duplex full
!
interface FastEthernet0/4
!
interface FastEthernet0/5
!
interface FastEthernet0/6
!
interface FastEthernet0/7
!
interface FastEthernet0/8
switchport mode access
switchport port-security
switchport port-security mac-address sticky
switchport port-security mac-address sticky 0002.dd7c.b789
!
interface FastEthernet0/9
!
interface FastEthernet0/10
!
interface FastEthernet0/11
!
interface FastEthernet0/12
!
interface FastEthernet0/13
!
interface FastEthernet0/14
!
interface FastEthernet0/15
switchport access vlan 20
switchport mode access
!
interface FastEthernet0/16
!
interface FastEthernet0/17
!
interface FastEthernet0/18
!
interface FastEthernet0/19
switchport access vlan 10
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/20
speed 100
!
interface FastEthernet0/21
!
interface FastEthernet0/22
!
interface FastEthernet0/23
!
interface FastEthernet0/24
switchport mode trunk
!
interface Vlan1
ip address 192.168.0.150 255.255.255.0
no ip route-cache
!
ip http server



Still have the same issue. I can ping boths sides of the routers interfaces but not the host on the other side of the router i.e in the other vlan.

Thanks

 

[burtsbees]

So the pc in vlan 10 cannot ping the pc in vlan 20, correct? Like pc1 can only ping up to the router, but not past it, and pc2 can only ping up to the router and not past it...correct? If so, post a full sh run from the router, and post sh int fa0/0.20, sh int fa0/0.10 from the router, and from the switch post sh int fa0/15 and sh int fa0/19. So far, what I see looks good. If everything in the posts I asked from you looks good, then check for Windows firewall...what OS on the pc's?

Burt

 

[jneiberger]

Back to the side topic, cabling is a physical matter. You need the right cable for physical, electrical connectivity no matter what application or purpose the connection has. Assuming you don't have Auto-MDI in place, you have to use a crossover cable between switches.