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Multiswitch VLANs Using Trunking

ERAM
Beginner
Beginner

Below is the network I have created using Packet Tracer (PT) v8.1.1.0022.

01.png

I have configured (2) static trunk ports between the 2960 switches. VTP mode is set to transparent. My configurations are shown below. The example and configuration steps were taken from Chapter 8 in W. Odom's CCNA 200-301 Cert Guide Vol. 1.


02.png


03.png


04.png


05.png


06.png


I can currently pass PDU's across the trunk as long as the communicating devices are in the same VLAN. The issue is that I am not able to pass PDU's across the trunk to different VLANs (e.g., PC11 to PC24).

I also do not see the configured trunk ports (G0/1 on both switches) listed in the output of the SH VL ID X command. Per the book example, I should see trunk port G0/1 in the output of SH VL ID X because the trunk port can forward traffic between VLANs 1, 10, 20.


07.png

Can someone please help me understand whether I am missing something, or if this could be a quirk of PT?

1 Accepted Solution

Accepted Solutions

Martin L
VIP Advisor VIP Advisor
VIP Advisor

 

it is good that u can pass traffic across the trunk as long as the communicating devices are in the same VLAN. For inter-vlan traffic communication u will need SVI on L3 switch or so called ROAS, router-on-a-stick.  in other words, B-cast domains are split because of vlans, and L3 device is needed.   Once router is added (ROAS) , your issue of "not able to pass PDU's across the trunk to different VLANs" will be solved.

you will learn ROAS later in the book.

PT is just a simulator and not all features are available or work the same way as real IOS.

 

Regards, ML
**Please Rate All Helpful Responses **

 

View solution in original post

8 Replies 8

balaji.bandi
VIP Community Legend VIP Community Legend
VIP Community Legend

Looks strange : below post output from both :

 

show vlan brief
show interfaces trunk
show interfaces switchport
show interfaces status
show spanning-tree

BB

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Below is the output of SHOW SPANNING-TREE for both switches. The other items you requested are included as screenshots in my original post.

SW1#sh sp
VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     0001.4280.92AA
             Cost        4
             Port        25(GigabitEthernet0/1)
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     0010.11CA.42CD
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/1            Root FWD 4         128.25   P2p

VLAN0010
  Spanning tree enabled protocol ieee
  Root ID    Priority    32778
             Address     0001.4280.92AA
             Cost        4
             Port        25(GigabitEthernet0/1)
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32778  (priority 32768 sys-id-ext 10)
             Address     0010.11CA.42CD
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/11           Desg FWD 19        128.11   P2p
Fa0/12           Desg FWD 19        128.12   P2p
Gi0/1            Root FWD 4         128.25   P2p

VLAN0020
  Spanning tree enabled protocol ieee
  Root ID    Priority    32788
             Address     0001.4280.92AA
             Cost        4
             Port        25(GigabitEthernet0/1)
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32788  (priority 32768 sys-id-ext 20)
             Address     0010.11CA.42CD
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/21           Desg FWD 19        128.21   P2p
Gi0/1            Root FWD 4         128.25   P2p
Fa0/22           Desg FWD 19        128.22  
P2p

 

SW2>sh sp
VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     0001.4280.92AA
             This bridge is the root
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     0001.4280.92AA
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/1            Desg FWD 4         128.25   P2p

VLAN0010
  Spanning tree enabled protocol ieee
  Root ID    Priority    32778
             Address     0001.4280.92AA
             This bridge is the root
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32778  (priority 32768 sys-id-ext 10)
             Address     0001.4280.92AA
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/14           Desg FWD 19        128.14   P2p
Fa0/13           Desg FWD 19        128.13   P2p
Gi0/1            Desg FWD 4         128.25   P2p

VLAN0020
  Spanning tree enabled protocol ieee
  Root ID    Priority    32788
             Address     0001.4280.92AA
             This bridge is the root
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32788  (priority 32768 sys-id-ext 20)
             Address     0001.4280.92AA
             Hello Time  2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/24           Desg FWD 19        128.24   P2p
Fa0/23           Desg FWD 19        128.23   P2p
Gi0/1            Desg FWD 4         128.25   P2p

balaji.bandi
VIP Community Legend VIP Community Legend
VIP Community Legend

Thank for the Information, Looks like you Layer 2 is ok, If you like Inter-vlan communication, you need to enable one of the device ip routing ?

 

does any of the device running ip-routing ?

BB

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Thank you for the ideas. @Martin L helped explain why I was getting hung up. It was helpful to recreate the book example to practice trunking configuration but there were some further L3 switching and routing concepts that need to be applied in order to make my design work.

Georg Pauwen
VIP Master VIP Master
VIP Master

Hello,

 

what are you trying to accomplish ? The switches you are using are L2 only, so three SVI (Vlan interfaces) will never be functional.

 

Either way, the Vlans do not show up on the trunk links in Packet Tracer, it is indeed one of the quirks. They just show up on the access ports.

My intent was to practice configuring VLAN trunking by recreating the multiswitch VLAN example from the book. Minus the port numbers, the screenshot below is essentially what I was trying to replicate.

08.png

To illustrate the lesson, I'm sure the book assumes a lot of configuration that goes unsaid. With that said, in this example, could you please explain why "three SVI (Vlan interfaces) will never be functional?"

To make sure I understand your second comment, are you saying that trunk ports not showing up in the output of SHOW VLAN ID X is indeed a quirk of Packet Tracer? So, only access ports would be shown in the output? I can accept that PT will not show that configuration. I mainly wanted to confirm that I wasn't misconfiguring something.

Martin L
VIP Advisor VIP Advisor
VIP Advisor

 

it is good that u can pass traffic across the trunk as long as the communicating devices are in the same VLAN. For inter-vlan traffic communication u will need SVI on L3 switch or so called ROAS, router-on-a-stick.  in other words, B-cast domains are split because of vlans, and L3 device is needed.   Once router is added (ROAS) , your issue of "not able to pass PDU's across the trunk to different VLANs" will be solved.

you will learn ROAS later in the book.

PT is just a simulator and not all features are available or work the same way as real IOS.

 

Regards, ML
**Please Rate All Helpful Responses **

 

Thank you! This makes complete sense. I have read beyond that so I understand what you're saying. I started using PT as a sim tool late in my studies so I've been going back and recreating some of the more complicated configs which I didn't practice early on.

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