Wednesday, July 30, 2008

today: Datacenter Switch Migration in a new RACK

No new topologies for today, the "exercise" is a real migration of switches in my actual datacenter environment.
The mission is to move existing switches from servers rack into a new dedicated Panduit rack (photos when finished, Panduit have great vert/hor cables management!).

There are: 2 x 4948 + 1 x 2960 really full, there are only 2 free ports!
In the new rack we will move: 2 x existing 4948 + 3 x new 4948. In addition, two of this 4948 will be used only for storage vlans (iscsi and nfs), these vlans aren't routed, but only L2.


Topology:



The first problem is how will reacts existing switches configured with STP 802.1D standard when i will add two new switch configured with RPVST+ (rapid stp, one process for each for vlan). Well this is adetail of one vlan in my production switches:

xxx#sh spanning-tree vlan 23 detail

VLAN0023 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, sysid 23, address 0019.e79d.1b00
Configured hello time 2, max age 20, forward delay 15
Current root has priority 32791, address 0015.fa7c.3c80
Root port is 45 (GigabitEthernet1/45), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 2071 last change occurred 2w6d ago
from GigabitEthernet1/27
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300
Ok, i will try to use a mixed STP environment, with 2 switches using traditional STP and 2 configured with RPSTP+.
I'll test it on my own lab before go into production system, because i want to know how are reacting traditional STP sw to avoiding STP to run on storage vlan (i don't want to destroy all in production! ;-)| )
So, this is the lab topology: (but i said "no new topologies for today?" ;-) a refresh of bcmsn!)

CON1 and CON2 will have STP 802.1D, CON3 and CON4 will have RPVSTP+ i'll activate the 2 links betw CON2 and CON3 and debug spanning-tree on all 4 switches to see what happens.

Here the 4 sw configuration [+/-]









CON1#CON2#CON3#spanning-tree mode rapid-pvstCON4#spanning-tree mode rapid-pvst
interface FastEthernet0/11
description Trunk CON1 <-> CON2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet0/12
description Trunk CON1 <-> CON2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface GigabitEthernet0/2
description Trunk CON1 <-> CON2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet0/3
description Trunk CON2 <-> CON3
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
shutdown
!
interface FastEthernet0/4
description Trunk CON2 <-> CON3
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
shutdown
!
interface FastEthernet0/11
description Trunk CON2 <-> CON1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet0/12
description Trunk CON2 <-> CON1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface GigabitEthernet0/2
description Trunk CON2 <-> CON1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet1/0/1
description Trunk CON3 <-> CON2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
shutdown
!
interface FastEthernet1/0/2
description Trunk CON3 <-> CON2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
shutdown
!
interface FastEthernet1/0/11
description Trunk CON3 <-> CON4
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet1/0/12
description Trunk CON3 <-> CON4
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet1/0/11
description Trunk CON4 <-> CON3
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
interface FastEthernet1/0/12
description Trunk CON4 <-> CON3
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-3
switchport mode trunk
!
CON1#sh spanning-tree summary
Switch is in pvst mode
Root bridge for: VLAN0001-VLAN0003
....
CON2#sh spanning-tree summary
Switch is in pvst mode
Root bridge for: none
....
CON3#sh spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: VLAN0001-VLAN0003
....
CON4#sh spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: none
....



Ok now i enable debug spanning-tree events and bring up links betw CON2 and CON3:

CON2#
01:53:51: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to up
01:53:51: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
01:53:52: set portid: VLAN0001 Fa0/3: new port id 8003
01:53:52: STP: VLAN0001 Fa0/3 -> listening
01:53:52: set portid: VLAN0002 Fa0/3: new port id 8003
01:53:52: STP: VLAN0002 Fa0/3 -> listening
01:53:52: set portid: VLAN0003 Fa0/3: new port id 8003
01:53:52: STP: VLAN0003 Fa0/3 -> listening
01:53:52: set portid: VLAN0001 Fa0/4: new port id 8004
01:53.52: STP: VLAN0001 Fa0/4 -> listening
01:53:52: set portid: VLAN0002 Fa0/4: new port id 8004
01:53:52: STP: VLAN0002 Fa0/4 -> listening
01:53:52: set portid: VLAN0003 Fa0/4: new port id 8004
01:53:52: STP: VLAN0003 Fa0/4 -> listening
01:53:53: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, changed state to up
01:53:53: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, changed state to up
01:53:56: STP: VLAN0001 Topology Change rcvd on Fa0/3
01:53:56: STP: VLAN0001 sent Topology Change Notice on Gi0/2
01:53:56: STP: VLAN0002 Topology Change rcvd on Fa0/3
01:53:56: STP: VLAN0002 sent Topology Change Notice on Gi0/2
01:53:56: STP: VLAN0003 Topology Change rcvd on Fa0/3
01:53:56: STP: VLAN0003 sent Topology Change Notice on Gi0/2
01:54:07: STP: VLAN0001 Fa0/3 -> learning
01:54:07: STP: VLAN0002 Fa0/3 -> learning
01:54:07: STP: VLAN0003 Fa0/3 -> learning
01:54:07: STP: VLAN0001 Fa0/4 -> learning
01:54:07: STP: VLAN0002 Fa0/4 -> learning
01:54:07: STP: VLAN0003 Fa0/4 -> learning
01:54:22: STP: VLAN0001 sent Topology Change Notice on Gi0/2
01:54:22: STP: VLAN0001 Fa0/3 -> forwarding
01:54:22: STP: VLAN0002 sent Topology Change Notice on Gi0/2
01:54:22: STP: VLAN0002 Fa0/3 -> forwarding
01:54:22: STP: VLAN0003 sent Topology Change Notice on Gi0/2
01:54:22: STP: VLAN0003 Fa0/3 -> forwarding
01:54:22: STP: VLAN0001 Fa0/4 -> forwarding
01:54:22: STP: VLAN0002 Fa0/4 -> forwarding
01:54:22: STP: VLAN0003 Fa0/4 -> forwarding
CON2#
Bingooo, only the upcoming port will transit upon spanning-tree states, other ports are not affected..
On CON3 we see CON2 as 802.1d


CON3#sh spanning-tree vlan 1

VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 32769
Address 0013.1a55.8000
Cost 23
Port 3 (FastEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 0014.a98c.8780
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/1 Root FWD 19 128.3 P2p Peer(STP)
Fa1/0/2 Altn BLK 19 128.4 P2p Peer(STP)
Fa1/0/11 Desg FWD 19 128.13 P2p
Fa1/0/12 Desg FWD 19 128.14 P2p




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