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Odd problem found during Q in Q setup
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Author:  boonchu.at.gns3 [ Tue Oct 07, 2014 4:08 pm ]
Post subject:  Odd problem found during Q in Q setup

Hello,

I ran into problem when I configured Q in Q by following the instructions from this site, http://www.gns3.net/articles/ccie-routi ... ch-option/ and see the odd problem that come from the gns3 router ping to real switch.

Topology:
Code:
version = 0.8.7
[127.0.0.1:7208]
    workingdir = /tmp
    udp = 10801
    [[3725]]
        image = /Volumes/media/Kickstart/cisco/c3725/C3725-AD.BIN
        idlepc = 0x60753be0
        sparsemem = True
    [[ROUTER R2]]
        model = 3725
        console = 2102
        aux = 2502
        cnfg = configs/R2.cfg
        f0/0 = SW1 2
        x = -293.0
        y = -22.0
        z = 1.0
[127.0.0.1:7200]
    workingdir = /tmp
    udp = 10001
    [[ETHSW SW1]]
        2 = access 102 R2 f0/0
        24 = dot1q 1 nio_gen_eth:en1
        x = -110.5
        y = -15.0
        z = 1.0
[GNS3-DATA]
    configs = configs
    [[NOTE 1]]
        text = "f0/0"
        x = 11.6096668809
        y = 56.8837879492
        interface = R2 f0/0
    [[NOTE 2]]
        text = "2"
        x = -16.1096668809
        y = 27.1162120508
        interface = SW1 2
    [[NOTE 3]]
        text = "nio_gen_eth:en1"
        x = -19.4998724626
        y = 56.3989902211
        interface = C1 nio_gen_eth:en1
    [[Cloud C1]]
        symbol = multilayer_switch
        x = 97.5
        y = -22.0
        z = 1.0
        connections = SW1:24:nio_gen_eth:en1


Cloud connect to breakout switch at port 48.
# breakout switch

Code:
system mtu routing 1998
vtp mode transparent
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
vlan dot1q tag native
!
vlan 102
!
interface FastEthernet0/3
description Downlink to SW01
switchport access vlan 102
switchport mode dot1q-tunnel
speed 100
duplex full
l2protocol-tunnel cdp
l2protocol-tunnel stp
l2protocol-tunnel vtp
no cdp enable
spanning-tree portfast
!
interface FastEthernet0/48
description Uplink to MacPRO
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-102
switchport mode trunk
speed 100
duplex full
l2protocol-tunnel cdp
l2protocol-tunnel stp
l2protocol-tunnel vtp
no cdp enable
spanning-tree portfast trunk
!


breakout switch connect to access switch with crossover cat6 cable at port 3.

Code:
interface FastEthernet0/3
switchport trunk encapsulation dot1q
switchport mode trunk
speed 100
duplex full
spanning-tree portfast
!


Here is router config.
Code:
!
interface FastEthernet0/0
no ip address
speed 100
full-duplex
!
interface FastEthernet0/0.10
encapsulation dot1Q 10
ip address 10.2.10.1 255.255.255.0
no snmp trap link-status
!
interface FastEthernet0/0.20
encapsulation dot1Q 20
ip address 10.2.20.1 255.255.255.0
no snmp trap link-status
!


I configure SPAN to observe the traffic from breakout.

When I switch on gns3 and real switch, both SW1 and R2 can be able to see CDP traffic fine.

Code:
R2#sh cdp ne
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
SW1              Fas 0/0            131         S I       WS-C3560-4Fas 0/3
R2               Fas 0/0            179        R S I      3725      Fas 0/0

Code:
R2#sh arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.2.10.1               -   c200.025d.0000  ARPA   FastEthernet0/0.10
Internet  10.2.20.1               -   c200.025d.0000  ARPA   FastEthernet0/0.20
Internet  10.2.20.254            30   0015.63c7.1ac3  ARPA   FastEthernet0/0.20
Internet  10.2.10.254            31   0015.63c7.1ac2  ARPA   FastEthernet0/0.10



Code:
SW1#sh cdp ne
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
R2               Fas 0/3           152             R S I  3725      Fas 0/0
SW1#sh arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.2.10.254             -   0015.63c7.1ac2  ARPA   Vlan10
Internet  10.2.20.1              32   c200.025d.0000  ARPA   Vlan20
Internet  10.2.20.254             -   0015.63c7.1ac3  ARPA   Vlan20


When I start pinging from R2 to SW1, problem starts.
ping to R1

Code:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.10.1, timeout is 2 seconds:
...!
01:31:22: ICMP: echo reply rcvd, src 10.2.10.1, dst 10.2.10.254, topology BASE, dscp 0 topoid 0.
Success rate is 20 percent (1/5), round-trip min/avg/max = 17/17/17 ms


try again, I got the same result. I can *always* see 1-2 ping reply from R1 router. either result is 20-40% succcessful...

Code:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.10.1, timeout is 2 seconds:
!
01:38:58: ICMP: echo reply rcvd, src 10.2.10.1, dst 10.2.10.254, topology BASE, dscp 0 topoid 0...!
Success rate is 40 percent (2/5), round-trip min/avg/max = 17/21/26 ms
SW1#
01:39:04: ICMP: echo reply rcvd, src 10.2.10.1, dst 10.2.10.254, topology BASE, dscp 0 topoid 0


ping to SW1 from R2 and observe with debug icmp flag on
switch replied with this:
Code:
01:32:58: ICMP: echo reply sent, src 10.2.10.254, dst 10.2.10.1, topology BASE, dscp 0 topoid 0
01:33:00: ICMP: echo reply sent, src 10.2.10.254, dst 10.2.10.1, topology BASE, dscp 0 topoid 0
01:33:02: ICMP: echo reply sent, src 10.2.10.254, dst 10.2.10.1, topology BASE, dscp 0 topoid 0


from tcpdump:
9:00:35.566919 IP (tos 0x0, ttl 255, id 40, offset 0, flags [none], proto ICMP (1), length 100)
10.2.10.1 > 10.2.10.254: ICMP echo request, id 8, seq 0, length 80
09:00:35.569652 IP (tos 0x0, ttl 255, id 40, offset 0, flags [none], proto ICMP (1), length 100)
10.2.10.254 > 10.2.10.1: ICMP echo reply, id 8, seq 0, length 80

but, R2 show ICMP failed.

Code:
R2#ping s10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.10.254, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)


I use native lan port from mac pro to breakout and configure with 100 Mb/s full duplex.

I have no idea what happens why the ping failed from both end.

Author:  boonchu.at.gns3 [ Tue Oct 07, 2014 4:11 pm ]
Post subject:  Re: Odd problem found during Q in Q setup

This is what I have from SPAN

No. Time Source Destination Protocol Length Info
15370 3760.066317000 10.2.10.254 10.2.10.1 ICMP 122 Echo (ping) request id=0x001d, seq=4/1024, ttl=255 (no response found!)

Frame 15370: 122 bytes on wire (976 bits), 122 bytes captured (976 bits) on interface 0
Ethernet II, Src: Cisco_c7:1a:c2 (00:15:63:c7:1a:c2), Dst: c2:00:02:5d:00:00 (c2:00:02:5d:00:00)
Destination: c2:00:02:5d:00:00 (c2:00:02:5d:00:00)
Source: Cisco_c7:1a:c2 (00:15:63:c7:1a:c2)
Type: 802.1Q Virtual LAN (0x8100)
802.1Q Virtual LAN, PRI: 0, CFI: 0, ID: 102
000. .... .... .... = Priority: Best Effort (default) (0)
...0 .... .... .... = CFI: Canonical (0)
.... 0000 0110 0110 = ID: 102
Type: 802.1Q Virtual LAN (0x8100)
802.1Q Virtual LAN, PRI: 0, CFI: 0, ID: 10
000. .... .... .... = Priority: Best Effort (default) (0)
...0 .... .... .... = CFI: Canonical (0)
.... 0000 0000 1010 = ID: 10
Type: IP (0x0800)
Internet Protocol Version 4, Src: 10.2.10.254 (10.2.10.254), Dst: 10.2.10.1 (10.2.10.1)
Internet Control Message Protocol
Type: 8 (Echo (ping) request)
Code: 0
Checksum: 0x07d0 [correct]
Identifier (BE): 29 (0x001d)
Identifier (LE): 7424 (0x1d00)
Sequence number (BE): 4 (0x0004)
Sequence number (LE): 1024 (0x0400)
[No response seen]
Data (72 bytes)

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