STP in Packet Tracer

sratakhinsratakhin Member Posts: 818
in CCNA & CCENT
I use Packet Tracer to do some simple labs. Right now, I'm labbing STP and I can't figure this out.Here is a screenshot of what my setup looks like:

Running-config from Switch0 (cut for brevity):
spanning-tree mode rapid-pvst
spanning-tree vlan 1 priority 0
spanning-tree vlan 3 priority 24576
interface FastEthernet0/11
switchport access vlan 3

interface FastEthernet0/16
switchport mode trunk
switchport nonegotiate

interface FastEthernet0/17
switchport mode trunk
switchport nonegotiate


Running-config from Switch1:
spanning-tree mode rapid-pvst
spanning-tree vlan 3 priority 0
spanning-tree vlan 1 priority 20480

interface FastEthernet0/12
switchport access vlan 3

interface FastEthernet0/16
switchport mode trunk
switchport nonegotiate

interface FastEthernet0/17
switchport mode trunk
switchport nonegotiate


As you see, I have 2 VLANs on the switches (configured with VTP). However, I'm trying to use different root bridges on vlans.Here is what I get when I run show spanning-tree:

Switch0
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 1
Address 0009.7C5A.25EA
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 1 (priority 0 sys-id-ext 1)
Address 0009.7C5A.25EA
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 20
Interface Role Sts Cost Prio.Nbr Type
---- ---
Fa0/16 Desg FWD 19 128.16 P2p
Fa0/17 Desg FWD 19 128.17 P2p
VLAN0003
Spanning tree enabled protocol rstp
Root ID Priority 24579
Address 0009.7C5A.25EA
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 24579 (priority 24576 sys-id-ext 3)
Address 0009.7C5A.25EA
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
Fa0/16 Desg FWD 19 128.16 P2p
Fa0/17 Desg FWD 19 128.17 P2p


Switch1:
VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 20481
Address 0001.644D.2BB3
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 20481 (priority 20480 sys-id-ext 1)
Address 0001.644D.2BB3
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 20
Interface Role Sts Cost Prio.Nbr Type
---- ---
Fa0/16 Desg FWD 19 128.16 P2p
Fa0/17 Desg FWD 19 128.17 P2p
VLAN0003
Spanning tree enabled protocol rstp
Root ID Priority 3
Address 0001.644D.2BB3
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 3 (priority 0 sys-id-ext 3)
Address 0001.644D.2BB3
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 20
Interface Role Sts Cost Prio.Nbr Type
---- ---
Fa0/16 Desg FWD 19 128.16 P2p
Fa0/17 Desg FWD 19 128.17 P2p
Fa0/12 Desg FWD 19 128.12 P2p


According to the outputs, both switches act as root bridges on both VLANs. How is it possible? Is it a bug in Packet Tracer or am I doing something wrong?
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Comments

  • NotHackingYouNotHackingYou Member Posts: 1,460 ■■■■■■■■□□
    It looks to me like the election isn't being held for some reason
    When you go the extra mile, there's no traffic.
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  • NotHackingYouNotHackingYou Member Posts: 1,460 ■■■■■■■■□□
    Oh also don't you have to use pvst to be able to get different VLANS to have different port roles? Looks like you are using RSTP but I think you need PVST.

    Edit: Also try typing in debug spanning-tree and then bouncing the interfaces. Observe the results in the console window for each switch.
    When you go the extra mile, there's no traffic.
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  • sratakhinsratakhin Member Posts: 818
    I'm using Rapid-PVST as the first line in each run-config says.
    Unfortunately, Packet Tracer doesn't support debugging icon_sad.gif
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  • NotHackingYouNotHackingYou Member Posts: 1,460 ■■■■■■■■□□
    Could you post the results of a sh int for each switch?
    When you go the extra mile, there's no traffic.
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  • carmelenigmacarmelenigma Member Posts: 12 ■□□□□□□□□□
    I just repeated the config in my own packet tracer and I got normal results. I just didnt include the nonegotiation statements because i didnt think they were needed.
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  • NotHackingYouNotHackingYou Member Posts: 1,460 ■■■■■■■■□□
    carmelenigma wrote: »
    I just repeated the config in my own packet tracer and I got normal results. I just didnt include the nonegotiation statements because i didnt think they were needed.

    The config looks correct to me. I suspect a problem with the interface config or maybe he selected the wrong cable type in PT? It's easy to do.
    When you go the extra mile, there's no traffic.
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  • sratakhinsratakhin Member Posts: 818
    I'm using crossover cables between the switches. The switches are 2960s.

    Switch0#sh int fa0/16
    FastEthernet0/16 is up, line protocol is up (connected)
    Hardware is Lance, address is 0060.5c59.0010 (bia 0060.5c59.0010)
    BW 100000 Kbit, DLY 1000 usec,
    reliability 255/255, txload 1/255, rxload 1/255
    Encapsulation ARPA, loopback not set
    Keepalive set (10 sec)
    Full-duplex, 100Mb/s
    input flow-control is off, output flow-control is off
    ARP type: ARPA, ARP Timeout 04:00:00
    Last input 00:00:08, output 00:00:05, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    Queueing strategy: fifo
    Output queue :0/40 (size/max)
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    956 packets input, 193351 bytes, 0 no buffer
    Received 956 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    0 watchdog, 0 multicast, 0 pause input
    0 input packets with dribble condition detected
    2357 packets output, 263570 bytes, 0 underruns
    0 output errors, 0 collisions, 10 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out

    Switch0#sh int fa0/17
    FastEthernet0/17 is up, line protocol is up (connected)
    Hardware is Lance, address is 0060.5c59.0011 (bia 0060.5c59.0011)
    BW 100000 Kbit, DLY 1000 usec,
    reliability 255/255, txload 1/255, rxload 1/255
    Encapsulation ARPA, loopback not set
    Keepalive set (10 sec)
    Full-duplex, 100Mb/s
    input flow-control is off, output flow-control is off
    ARP type: ARPA, ARP Timeout 04:00:00
    Last input 00:00:08, output 00:00:05, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    Queueing strategy: fifo
    Output queue :0/40 (size/max)
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    956 packets input, 193351 bytes, 0 no buffer
    Received 956 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    0 watchdog, 0 multicast, 0 pause input
    0 input packets with dribble condition detected
    2357 packets output, 263570 bytes, 0 underruns
    0 output errors, 0 collisions, 10 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out

    ___________________________________

    Switch1#sh int f0/16
    FastEthernet0/16 is up, line protocol is up (connected)
    Hardware is Lance, address is 0006.2ac8.8410 (bia 0006.2ac8.8410)
    BW 100000 Kbit, DLY 1000 usec,
    reliability 255/255, txload 1/255, rxload 1/255
    Encapsulation ARPA, loopback not set
    Keepalive set (10 sec)
    Full-duplex, 100Mb/s
    input flow-control is off, output flow-control is off
    ARP type: ARPA, ARP Timeout 04:00:00
    Last input 00:00:08, output 00:00:05, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    Queueing strategy: fifo
    Output queue :0/40 (size/max)
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    956 packets input, 193351 bytes, 0 no buffer
    Received 956 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    0 watchdog, 0 multicast, 0 pause input
    0 input packets with dribble condition detected
    2357 packets output, 263570 bytes, 0 underruns
    0 output errors, 0 collisions, 10 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out




    Switch1#sh int f0/17
    FastEthernet0/17 is up, line protocol is up (connected)
    Hardware is Lance, address is 0006.2ac8.8411 (bia 0006.2ac8.8411)
    BW 100000 Kbit, DLY 1000 usec,
    reliability 255/255, txload 1/255, rxload 1/255
    Encapsulation ARPA, loopback not set
    Keepalive set (10 sec)
    Full-duplex, 100Mb/s
    input flow-control is off, output flow-control is off
    ARP type: ARPA, ARP Timeout 04:00:00
    Last input 00:00:08, output 00:00:05, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    Queueing strategy: fifo
    Output queue :0/40 (size/max)
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    956 packets input, 193351 bytes, 0 no buffer
    Received 956 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    0 watchdog, 0 multicast, 0 pause input
    0 input packets with dribble condition detected
    2357 packets output, 263570 bytes, 0 underruns
    0 output errors, 0 collisions, 10 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out
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  • carmelenigmacarmelenigma Member Posts: 12 ■□□□□□□□□□
    It looks like your lines are all up so cabling is good, how about a show run?
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  • ccnxjrccnxjr Member Posts: 304 ■■■□□□□□□□
    Just curious,
    Are those links to the PC's configured as trunks?
    It's hard to tell how you got them cabled up, could be you have them plugged into mismatched ports?
    Can't tell which port is connected to what from the picture.
    Also, what version of packet tracer are you using?
    I plugged your config into version 5.2.1.0008 and it seems to work.
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  • sratakhinsratakhin Member Posts: 818
    Hm... I did some changes to the configurations and now it's working correctly. Wondering what caused it... The only thing that is different in running-config is that I no longer use ​switchport no-negotiate

    The PCs are connected to access ports. I'm using PT 5.3.3
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  • NotHackingYouNotHackingYou Member Posts: 1,460 ■■■■■■■■□□
    Could you also post a sh vtp and a sh run please?
    When you go the extra mile, there's no traffic.
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  • NotHackingYouNotHackingYou Member Posts: 1,460 ■■■■■■■■□□
    Glad you got it going!
    When you go the extra mile, there's no traffic.
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  • sratakhinsratakhin Member Posts: 818
    Thank you for the suggestion.
    I'm trying to replicate the problem again and I can't :)
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  • carmelenigmacarmelenigma Member Posts: 12 ■□□□□□□□□□
    maybe just a hiccup,it happens
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  • sratakhinsratakhin Member Posts: 818
    I scratched my head for almost two hours... Guess I'd finally better invest in a real lab. Or just grab some ProCurves from work.
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  • inscom.brigadeinscom.brigade Member Posts: 400 ■■■□□□□□□□
    glad you got it,
    but don't begin to think that it will get easyer with real lab gear; that is when the fun begins.

    Most of us build labs on a budget=mismatched and undesirable components, inadiquite memory old stuff EOL/EOS, pc's,servers, not good enough all to offten.
    AND what are we trying to emulate | ( latest technology enterprise/campus design) | #&^%$@! <- give yourself a break good job!
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