4108GL routing between VLAN issue

[cachuque]

Hello,

I'm configuring 2 HP 4108GL with VLAN and IP routing.

Switch A
========
It has 5 VLAN.
hostX is connected to VLAN1. Port E15 (It has configured default gateway 192.168.14.250)
hostY is connected to VLAN4. Port D9  (It has configured default gateway 192.168.128.250)

When hostX ping hostY, all the packets go to the Switch B.

hostX (switch A) --> Switch B --> hostY (switch A) --> Switch B --> hostX (switch A)


Why the packets goes to the switch B? The switch can ping directly the two hosts.



I obtain the same result when I configure the switch A with or without "ip routing". The IP traffic always goes to switch B. (When I configure the switch without "ip routing", I delete all routes).

The switch B (IP 192.168.14.250) is connected directly on port H20 (VLAN1). It has a similar configuration.

Switch A. show run:
===================

ip default-gateway 192.168.14.254
sntp server 192.158.0.56
ip routing
no timesync
snmp-server community "xxxxxx" Unrestricted
vlan 1
   name "vlMELDC"
   untagged A1-A24,E1-E24,F5-F6,F11-F22,G21-G22,H20-H22
   ip address 192.168.14.251 255.255.255.0
   no untagged B1-B24,C1-C24,D1-D24,F1-F4,F7-F10,G1-G20,H1-H19
   ip igmp
   exit
vlan 2
   name "vlMELOF"
   untagged B1-B24
   ip address 192.168.63.251 255.255.255.0
   ip helper-address 192.168.14.10
   tagged F16,F20-F22,G21-G22,H20-H22
   ip igmp
   exit
vlan 4
   name "vlSBD"
   untagged D1-D24,H1-H19
   ip address 192.168.128.249 255.255.255.0
   tagged F16,F20-F22,G21-G22,H20-H22
   ip igmp
   exit
vlan 5
   name "vlNAP"
   untagged C1-C24,G1-G20
   ip address 192.168.120.1 255.255.255.0
   tagged F16,F20-F22,G21-G22,H20-H22
   ip igmp
   exit
vlan 6
   name "vlMIDDLETOWN"
   untagged F1-F4,F7-F10
   ip address 192.168.126.249 255.255.255.0
   tagged F16,F20-F22,H20-H22
   ip igmp
   exit
ip route 0.0.0.0 0.0.0.0 192.168.14.15
ip route 192.168.0.0 255.255.0.0 192.168.14.254
ip route 10.0.0.0 255.0.0.0 192.168.14.254
ip route 192.168.250.0 255.255.255.0 192.168.14.15
ip route 172.16.2.0 255.255.255.0 192.168.14.15
ip route 172.16.1.0 255.255.255.0 192.168.14.254
spanning-tree
spanning-tree protocol-version STP
spanning-tree F13 mode Fast




Show ip route
=============

                                IP Route Entries

  Destination     Network Mask    | Gateway         Type      Sub-Type   Metric
  --------------- --------------- + --------------- --------- ---------- ------
  0.0.0.0         0.0.0.0         | 192.168.14.15   static               1
  10.0.0.0        255.0.0.0       | 192.168.14.254  static               1
  127.0.0.0       255.0.0.0       | reject          static               0
  127.0.0.1       255.255.255.255 | lo0             connected            0
  172.16.1.0      255.255.255.0   | 192.168.14.254  static               1
  172.16.2.0      255.255.255.0   | 192.168.14.15   static               1
  192.168.0.0     255.255.0.0     | 192.168.14.254  static               1
  192.168.14.0    255.255.255.0   | vlMELDC         connected            0
  192.168.63.0    255.255.255.0   | vlMELOF         connected            0
  192.168.120.0   255.255.255.0   | vlNAP           connected            0
  192.168.126.0   255.255.255.0   | vlMIDDLETOWN    connected            0
  192.168.128.0   255.255.255.0   | vlSBD           connected            0
  192.168.250.0   255.255.255.0   | 192.168.14.15   static               1

[RK_br]

Hello cachuque,

The issue is the default gateway for your hosts. Since the hosts can only see Layer 2, they will always send L3 packets to their GW. If you change your default GW to the IP address on Switch A, this should be resolved.

Best of luck,

RK

[cachuque]

Thanks RK,

I have configured the default gateway in the hosts. All the IP traffic are responding between hosts.
But, sometimes, without traffic, the time of the ping response increases, and all became slow.

This situation is cyclic:

Ping from host in VLAN1 (switch A, also its dfgw) to host in VLAN4 (switch B, also its dfgw)

Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=3ms TTL=127
Reply from 192.168.128.7: bytes=32 time<1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=2ms TTL=127
Reply from 192.168.128.7: bytes=32 time<1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=23ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=20ms TTL=127
Reply from 192.168.128.7: bytes=32 time=13ms TTL=127
Reply from 192.168.128.7: bytes=32 time<1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=6ms TTL=127
Reply from 192.168.128.7: bytes=32 time=13ms TTL=127
Reply from 192.168.128.7: bytes=32 time=14ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=10ms TTL=127
Reply from 192.168.128.7: bytes=32 time=13ms TTL=127
Reply from 192.168.128.7: bytes=32 time=7ms TTL=127
Reply from 192.168.128.7: bytes=32 time=10ms TTL=127
Reply from 192.168.128.7: bytes=32 time=2ms TTL=127
Reply from 192.168.128.7: bytes=32 time=4ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=3ms TTL=127
Reply from 192.168.128.7: bytes=32 time=2ms TTL=127
Reply from 192.168.128.7: bytes=32 time=2ms TTL=127
Reply from 192.168.128.7: bytes=32 time=3ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127
Reply from 192.168.128.7: bytes=32 time=1ms TTL=127

I don't know the reason of this. The switches seems well configured. But every few seconds, this situation is repeated.