Cisco Noob - Layer 3 Routing / VLAN / Spanning Tree
Hi All ...
I need some pointers on which commands / settings and where, I know what I want to achieve but the things I am trying seem to be 'mutually exclusive' - either that or i'm missing something - I am not a Cisco IOS expert but I know my way around a network.
Take 3 3560 switches in Layer 3 mode, there is a 'local' fibre spanning tree ring serving mulriple switches on each, each ring is it's own IP segment / VLAN. There is then a trunk between each switch on which I want to establish a load sharing / spanning tree circuit i.e.
SW1 hosts VLAN 2 via copper on fa0/1 -12, ip address 10.10.2.254
SW1 hosts VLAN 3 via a fibre spanning tree circuit on G0/1 & G0/2, dhcp 10.10.3.0/24, trunk 1 on G0/3 and trunk 2 on G0/4
SW1 hosts VLAN 10, ip address 10.10.10.1 (trunks 1 and 2 have no IP address but are members of VLAN 10)
SW2 hosts VLAN 4 via a fibre spanning tree circuit on G0/1 & G0/2, dhcp 10.10.4.0/24, trunk 1 on G0/3 and trunk 2 on G0/4
SW2 hosts VLAN 10, ip address 10.10.10.2 (trunks 1 and 2 have no IP address but are members of VLAN 10)
SW3 hosts VLAN 5 via a fibre spanning tree circuit on G0/1 & G0/2, dhcp 10.10.5.0/24, trunk 1 on G0/3 and trunk 2 on G0/4
SW3 hosts VLAN 10, ip address 10.10.10.3 (trunks 1 and 2 have no IP address but are members of VLAN 10)
SW1 G0/3 is a SMF trunk to SW2 G0/3
SW1 G0/4 is a SMF trunk to SW3 G0/3
SW2 G0/4 is a SMF trunk to SW3 G0/4
The trunks are configured as "trunk encapsulation dot1q", ip routing is enabled.
I can get the trunks working OK - but I can't seem to get routing to work across them - if I define an interface on SW1 with an IP set in SW3 the switch complains so it can clearly see it so which command have I missed.
All VLAN's are part of the same domain, each VLAN has it's own DHCP hosted on it's hosting switch. The VLAN ip address is excluded from DHCP and is the default gateway for each VLAN.
All VLAN's must be able to reach VLAN2 (contains SQL servers and DNS, Time etc etc), the VLAN's are working, DHCP etc is all working - but I can't get anything other than VLAN 10 IP's to talk across the trunks - I've tried adding spanning-tree vlan 2,3,4,5,10 but this hasn't worked, the ip route-map shows nothing, if you show spanning-tree the trunk ports do show up as an interface for all VLAN's - and yet no traffic passes across them - show route displays nothing. I tried adding ip route 10.10.*.0 255.255.255.0 10.10.2.254 (where 10.10.2.254 is the ip address of VLAN 2) but that's done nothing.
I have tried various combinations - unsuccessful so far - I need the trunks to be not only fault tolerant but load sharing which kind of negates fixing IP's on them - or does it ?? - what am I missing ?
(switches are all running IP services IOS)
Hi John ,, here is the sh ip route and sh ip eigrp from all three.
The ip address I'm trying to reach from SW1, SW2 is 10.10.2.253 - the DNS server - the server is available and connected to a copper port designated and assigned to VLAN 2 (which has the root ip of 10.10.2.254) dhcp is not enabled for VLAN 2.
I can ping the DNS box from VLAN 5 (same switch as VLAN 2).
The copper ports on the SW1 and SW2 boxes refuse to 'come up' - they remain shutdown no matter what. I haven't yet configured VLAN 10 ....
(NOTE - these switches are on the bench right now - I intend to ge tthe config sorted / tested and verified before they go into production)
SWITCH 1 - Host for VLAN 3 and 10
SW1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
D 10.10.2.0/24 [90/3072] via 10.10.10.6, 01:19:29, GigabitEthernet0/2
C 10.10.10.0/30 is directly connected, GigabitEthernet0/1
C 10.10.10.4/30 is directly connected, GigabitEthernet0/2
SW1#sh ip eigrp interfaces
EIGRP-IPv4:(10) interfaces for process 10
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Gi0/2 1 0/0 1 0/1 0 0
Vl3 0 0/0 0 0/1 0 0
SW1#
SWITCH 2 - Host for VLAN 4 and 10
SW2#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
10.0.0.0/30 is subnetted, 2 subnets
C 10.10.10.8 is directly connected, GigabitEthernet0/1
C 10.10.10.0 is directly connected, GigabitEthernet0/2
SW2#sh ip eigrp interfaces
EIGRP-IPv4:(10) interfaces for process 10
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Gi0/2 0 0/0 0 0/1 0 0
Gi0/1 0 0/0 0 0/1 0 0
Vl4 0 0/0 0 0/1 0 0
SW2#
SWITCH 3 - Host for VLAN 2, 5 and 10
SW3#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.10.10.8/30 is directly connected, GigabitEthernet0/1
C 10.10.2.0/24 is directly connected, Vlan2
C 10.10.10.4/30 is directly connected, GigabitEthernet0/2
SW3#sh ip eigrp interfaces
EIGRP-IPv4:(5) interfaces for process 5
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Vl2 0 0/0 0 0/1 0 0
Vl5 0 0/0 0 0/1 0 0
EIGRP-IPv4(0)(0) interfaces for process 0
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
EIGRP-IPv4:(10) interfaces for process 10
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Gi0/2 1 0/0 1 0/1 50 0
Vl5 0 0/0 0 0/1 0 0
Vl2 0 0/0 0 0/1 0 0
SW3#
SW3#show vlan
VLAN Name Status Ports
1 default active
2 SERVERS active Fa0/13, Fa0/14, Fa0/15, Fa0/16
Fa0/17, Fa0/18, Fa0/19, Fa0/20
4 DB5-LAN active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Gi0/1, Gi/2
10 MANAGER active Fa0/21, Fa0/22, Fa0/23, Fa0/24
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
1 enet 100001 1500 - - - - - 0 0
2 enet 100002 1500 - - - - - 0 0
3 enet 100003 1500 - - - - - 0 0
4 enet 100004 1500 - - - - - 0 0
5 enet 100005 1500 - - - - - 0 0
10 enet 100010 1500 - - - - - 0 0
1002 fddi 101002 1500 - - - - - 0 0
1003 tr 101003 1500 - - - - srb 0 0
1004 fdnet 101004 1500 - - - ieee - 0 0
1005 trnet 101005 1500 - - - ibm - 0 0
Remote SPAN VLANs
Primary Secondary Type Ports
PPS : I'm using ports Gi0/1 and Gi0/2 for now - I removed these from DB5-LAN and can now 'ping' from SW1 but not from SW2 - but the local copper is still dead on SW1 and SW2
Copper channels not dead - faulty patch lead ... the simplest things ....
Similar Messages
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VLAN spanning-tree root and VLAN L3 SVI
I have a traditional core/access switches connected, Catalyst 4506 with 802.1Q uplink trunks to two core 6504-E switches. Spanning-tree roots for VLAN's were on core switch with the active HSRP/SVI. Shutdown HSRP/SVI on the cores and moved the SVI to the L3 access switches, but we left the spanning-tree root on the cores... Is this causing the clients/ports in the VLAN on the access switches to do a double/triple hop over the uplink for ingress/egress? Gig1/1 is the trunkport/uplink to the core, wanted to move L3 functions to the access switch to reduce spanning VLANs across the core network.
Current configuration : 253 bytes
interface Vlan196
description Tower I - 8th Floor VLAN
ip address 10.200.196.1 255.255.255.0
ip access-group 115 in
ip helper-address 164.103.160.150
ip helper-address 172.20.135.201
no ip redirects
no ip unreachables
ip pim sparse-mode
end
I0504506A8#sh spann
I0504506A8#sh spanning-tree vlan 196
VLAN0196
Spanning tree enabled protocol ieee
Root ID Priority 196
Address 6400.f1ee.c140
Cost 4
Port 1 (GigabitEthernet1/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 49348 (priority 49152 sys-id-ext 196)
Address 0015.f960.9ac0
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Role Sts Cost Prio.Nbr Type
Gi1/1 Root FWD 4 128.1 P2p
Gi1/2 Altn BLK 4 128.2 P2pHi Tojackson, I guess this depends on how stuff is interconnecting. It's obvious gi1/1 is forwarding and gi1/2 is blocking. So from the furthest access switch, what path must it take to reach gi1/1? That is the number of hops involved for normal traffic.
Now, if you're concerned about a specific VLAN and you need gi1/2 forwarding to reduce travel time for other traffic, you may employ RPVST to have that specific VLAN and cost to go to gi1/2.
In some part of the network I support we have a pair of Cisco 7606 which feeds in to a 4507R and off the 4507R we have a ring of 2955 with even 10-12 L2 switches on the ring. The consequence of multiple layer 2 hops is not of much concern and our spanning tree stops with the 4507 since we're not concerned about broadcast storm on the routed interfaces on the 7600.
-Tom
Please mark answered for helpful posts -
VLAN Spanning-tree (VSTP) issue with Metro-E links
Hi Everyone,
We have Juniper EX 4200 as core switch at two sites connected Cisco 2960s and Cisco 3560s (access layer switches). For even-numbered VLANs, one Juniper switch is root bridge and for odd-numbered VLANs, other Juniper switch is the root bridge.
We have Cox and Verizon Metro-E links connecting core switches (Juniper EX 4200 at both sites).
I want to do VLAN load sharing using VSTP but somehow it is not working as expected. I want to pass some VLANs through COX and some through Verizon. When there is any issue with Cox, all VLAN traffic pass through Verizon and vice-versa. RSTP is also enabled on both Juniper switches.
I see MAC flapping in log messages on all Cisco access layer switches when I bring up both Metro-E links together. When only Cox is connected, everything works fine. When only Verizon is connected, everything works fine. But when BOTH COX and Verizon are connected, network gets disrupt and I see MAC flapping on all Cisco switches. All cisco switches are running PVST.
Anybody knows what is happening and why VSTP is not working when both COX and VERIZON Metro-E links are active ?Hi Tojackson, I guess this depends on how stuff is interconnecting. It's obvious gi1/1 is forwarding and gi1/2 is blocking. So from the furthest access switch, what path must it take to reach gi1/1? That is the number of hops involved for normal traffic.
Now, if you're concerned about a specific VLAN and you need gi1/2 forwarding to reduce travel time for other traffic, you may employ RPVST to have that specific VLAN and cost to go to gi1/2.
In some part of the network I support we have a pair of Cisco 7606 which feeds in to a 4507R and off the 4507R we have a ring of 2955 with even 10-12 L2 switches on the ring. The consequence of multiple layer 2 hops is not of much concern and our spanning tree stops with the 4507 since we're not concerned about broadcast storm on the routed interfaces on the 7600.
-Tom
Please mark answered for helpful posts -
Cisco Switches and HP Interoperability with Spanning-Tree (RSTP)
Hello All.
I read a lot of information from this forum about Spaning-Tree interoperability between HP Switches and Cisco Switches.
Rather than having questions I would like to post that I manage to configure successfully HP and Cisco using RSTP (802.1w).
SWPADRAO]display stp root
MSTID Root Bridge ID ExtPathCost IntPathCost Root Port
0 32768.cc3e-5f3a-2939 0 0
[SWPADRAO]display stp brief
MSTID Port Role STP State Protection
0 GigabitEthernet1/0/47 DESI FORWARDING NONE
0 GigabitEthernet1/0/48 DESI FORWARDING NONE
[SWPADRAO]display stp instance 0
-------[CIST Global Info][Mode RSTP]-------
CIST Bridge :32768.cc3e-5f3a-2939
Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC :32768.cc3e-5f3a-2939 / 0
CIST RegRoot/IRPC :32768.cc3e-5f3a-2939 / 0
CIST RootPortId :0.0
BPDU-Protection :enabled
Bridge Config-
Digest-Snooping :disabled
TC or TCN received :17
Time since last TC :0 days 0h:1m:52s
SWNHAM17#show spanning-tree VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 32768
Address cc3e.5f3a.2939
Cost 4
Port 26 (GigabitEthernet0/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 61441 (priority 61440 sys-id-ext 1)
Address 001b.54db.7200
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 Interface Role Sts Cost Prio.Nbr Type
Gi0/1 Altn BLK 4 128.25 P2p
Gi0/2 Root FWD 4 128.26 P2p
SWNHAM18#show spanning-tree VLAN0001
Spanning tree enabled protocol rstp
Root ID Priority 32768
Address cc3e.5f3a.2939
Cost 4
Port 26 (GigabitEthernet0/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 61441 (priority 61440 sys-id-ext 1)
Address 001b.0cbc.4300
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 Interface Role Sts Cost Prio.Nbr Type
Gi0/1 Desg FWD 4 128.25 P2p
Gi0/2 Root FWD 4 128.26 P2pHello, David.
Your command doesn't work because it's made only for tha ports that has command "spanning-tree portfast" in them. Try change spanning tree mode at the HP switch to MSTP if this is possible. -
Spanning Tree and Admin mac address issues srw2048
Ok, I have a somewhat complex problem and hopefully someone may shed some light or have an idea as to whats wrong.
First the scenario:
I have two Cisco Cat 6509's etherchanneled to each other via two fiber cables. One of these is the STP/RSTP root. I have two SRW2048's.. one trunked to each of these 6509 switches. There is also a trunk between the SRW2048's. All this is to create a redundant topology so that if one of the switches fail's the others can still forward packets to each other. Of course the scenario described is in fact a loop that should be handled by STP/RSTP. I have RSTP enabled on all the switches in the scenario (PV RSTP on the cisco switches as they only do Cisco's brand of per vlan spanning tree). There are 3 vlan's configured on each of the srw2048's (2,55,96). There are corresponding vlan's also on the 6509's. I have put the srw2048's management interface into vlan 2.
The problem:
I need to forward packets between the srw2048's primarily and only use the 6509 that is not the root when a failure happens. I have configured the non-root 6509's spanning tree cost on the etherchannel to be higher then the alternate path through the srw's to the root. I can hook everything up and view the spanning tree and see that the srw2048's interface that goes to the non-root 6509 is blocked, and all other interfaces on the other switches are forwarding. I can in fact ping and get to the admin interface on all the switches. Then for some strange reason the admin interface of the srw2048 plugged into the non-root 6509 stops responding. If I disable either the interface its plugged into on the 6509 or the other srw2048 everything starts working again. Sometimes it responds after many failures for no apparent reason. I looked into the mac-address table on the 6509's and they are conflicting, pointing to each other for the mac-address of the broken srw2048. When I clear the mac-table the admin port comes back for about 5 seconds then again goes dark. When reviewing mac-table on the 6509's they are back to pointing to each other. The odd thing (although I haven't confirmed this completely) is that hosts placed into vlan 2 on that same srw2048 seem to work fine. If there was an STP loop or something misconfigured, I would expect it to effect any host in vlan 2 or the other vlan's for that matter on the srw2048 that stops responding. Alas, I am stuck because I need to manage this switch remotely. My only thought is that for some reason even when the STP status is blocked the broken srw2048 is still sending out arp's of its admin interface and bypassing the STP protocol. I have no way to confirm this, but maybe someone has an idea as to what I'm doing wrong, or otherwise offer a solution. For now, I simply removed vlan 2 from the 6509 that the broken srw2048 is plugged into and everything seems fine.
My apologies for such a long post, but this is somewhat complicated. Thanks in advance for any info.
-Geoff
Message Edited by gmyers on 08-19-2008 10:35 PMTo follow up, I had a ticket open with Linksys about this for about 3 months with no resolution. I submitted packet captures, stp outputs, etc and no luck. I gave up and basically had to revert to a manual failover for redundancy. It's no perfect or fast, but it works every time.
Unless linksys issues a firmware upgrade with this as a fix, I doubt we will be able to ever resolve this on our own. -
Spanning Tree VLAN Priority Issue
We have two 6500E switches and running spanning tree with rapid-pvst.We have also configured per vlan spanning tree priority with 100,200 so odd vlan have one switch hight priority and even vlans have another switch high priority.
I have created new vlan 10 and tring to add spanning tree priority to the switches i am getting the following error
Core-switch(config)#spanning-tree vlan 10 priority 100
% Bridge Priority must be in increments of 4096.
% Allowed values are:
0 4096 8192 12288 16384 20480 24576 28672
32768 36864 40960 45056 49152 53248 57344 61440
Can some experts help me why i am getting the above message and how can i add the priority to the same as existing vlansHi ,
Spanning tree priority can be set in increment of 4096 , any other values will be rejected . if you want to know about priority value of existing vlan execute command show spanning-tree vlan X / show spanning-tree command which will show you switch priority value
Step 2
spanning-tree vlan vlan-idpriority priority
Configure the switch priority of a VLAN.
•For vlan-id, you can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma. The range is 1 to 4094.
•For priority, the range is 0 to 61440 in increments of 4096; the default is 32768. The lower the number, the more likely the switch will be chosen as the root switch.
Valid priority values are 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, and 61440. All other values are rejected.
HTH
Sandy -
I have a CAT4006 with 2 layer-2 uplinks to 2 CAt3750 switches respectively
CAT4006 as PLWARBITES008 connected to:
Connection 1
============
PLWARBITES008 (G1/1)connected to PLWARBITMP001 (G1/0/8)
Note: Connection down
Connection 2
============
PLWARBITES008 (G1/2)connected to PLWARBITMP002 (G1/0/8)
NOte: Connection is up
The connection 1 is down, however,
if I show cdp nei G1/1 in PLWARBITES008,
(Seems connected to itself)
I got this:
PLWARBITES008#sh cdp nei GigabitEthernet1/1 det
Device ID: PLWARBITES008
Entry address(es):
IP address: 134.1.1.1
Platform: cisco WS-C4006, Capabilities: Switch IGMP
Interface: GigabitEthernet1/1, Port ID (outgoing port): GigabitEthernet1/1
Holdtime : 145 sec
Version :
Cisco IOS Software, Catalyst 4000 L3 Switch Software (cat4000-I5S-M), Version 12.2(25)EWA1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
However, in PLWARBITMP001 (g1/0/80), the serial and line protocol are down. Can I know why is it like that?Hi:
That is called PVSTP , Per vlan Spanning tree protocol. It is default feature with L2 & L3 switches of Cisco. One connection is in forwarding state & one is in blocking state.
regards
Sandipani C -
Refering to these two links
http://www.cisco.com/en/US/tech/tk389/tk390/technologies_tech_note09186a0080094665.shtml
http://www.experts-exchange.com/Hardware/Routers/Q_21349385.html
IEEE 802.1Q defines a single instance of spanning tree running on the native VLAN for all the VLANs in the network which is called Mono Spanning Tree (MST). This lacks the flexibility and load balancing capability of PVST available with ISL. However, PVST+ offers the capability to retain multiple Spanning Tree topologies with 802.1Q trunking.
IEEE 802.1Q defines a single instance of spanning tree running on the native VLAN for all the VLANs in the network which is called Mono Spanning Tree (MST). This lacks the flexibility and load balancing capability of PVST available with ISL. However, PVST+ offers the capability to retain multiple Spanning Tree topologies with 802.1Q trunking.
http://networking.ringofsaturn.com/Certifications/BCMSN.php
Per-VLAN Spanning Tree (PVST) ? A Cisco proprietary method of connecting through 802.1Q VLAN trunks, the switches maintain one instance of the spanning tree for each VLAN allowed on the trunk, versus non-Cisco 802.1Q switches which maintain one instance for ALL VLANs. This is the default STP used on ISL trunks.
http://www.informit.com/content/images/1587051427/samplechapter/1587051427content.pdf
The 802.1Q standard defines one unique Spanning Tree instance to be used by all VLANs in the network. STP runs on the Native VLAN so that it can communicate with both 802.1Q and non-802.1Q compatible switches. This single instance of STP is often referred to as 802.1Q Mono Spanning Tree or Common Spanning Tree (CST). A single spanning tree
lacks flexibility in how the links are used in the network topology. Cisco implements a protocol known as Per-VLAN Spanning Tree Plus (PVST+) that is compatible with 802.1Q CST but allows a separate spanning tree to be constructed for each VLAN. There is only one active path for each spanning tree; however, in a Cisco network, the active path can be
I could not get exactly what these Terminology (PVST, instance, PVST+, MST, etc) trying to achieve ?
Any URL and online resource help me to do some extar reading to clarify these terminologyHi,
The URLs that you have provided all explains the same technical details in different fashion.
I will summarise them here for better clarity.
There are two separate technologies that needs clarity.
1) Method of Trunking many vlans across a link
2) Spanning tree
Now for point 1, we have the IEEE standard 802.1q, which mentions how multiple vlans can be carried across a link. As per this standard a 4 byte tag will be inserted in the ethernet packet, ( inserted between the Destination mac address field and the ethertype field)
This tag will contain the vlan identifier info and some other details ( available in the urls that you have highlighted)
Cisco has a proprietary technology called ISL which effectively does the same job in a different fashion but can only be used in cisco devices.
Now for point 2, again we have IEEE standards like 802.1d ( common/mono spanning tree), 802.1w/RSTP ( Rapid spanning tree) and 802.1s/MSTP.
In 802.1d, there will be only one spanning tree process/instance running for the whole network, irrespective of how many vlans are involved in the network. Hence the whole network is treated as one common domain by the STP protocol.
So, there can be only one root bridge in the network and other bridges will intelligently block the redundant links, we wont have much control to effectively utilise the redundant links.
IEEE 802.1w/RSTP also works in the same fashion, but the convergence time is very fast in this protocol.
Here also there is only one spanning tree instance involved.
In both the above STP protocols, there is only one instance/process of the protocol running in the network, which is common for all vlans. Hence these protocols consume only very less CPU utilisation.
In 802.1s/ MSTP ( multiple spanning tree), extends the 802.1w Rapid Spanning Tree Protocol (RSTP) to have multiple STP instances. In this protocol, we can group the desired vlans in to one Instance of the protocol.
Say for example, lets assume a typical campus network with multiple access switches, 2 distribution/core switches.
Access switches having dual connectivity to the distribution/core switches.
In this topology if we deploy 802.1d or 802.1w, the redundant links from the access switches to the distribution/core switches will be blocked. Only one uplink from the access switch to the distribution layer will be working at any point.
In this network, only one distribution/core switch will be root bridge for the entire network.
But if we deploy 802.1s for this network, we can design it as follows.
We can split the vlans in to two groups,
Group1 => vlan 1 to 50
Group2 => vlan 51 to 100
We can create two instance of MSTP protocol with the following mappings
Instance 1 => for Group 1, with one distribution/core switch as the root bridge
Instance 2 => for Group 2, with another distribution switch as the root bridge
--Continued -
ESW 500 Spanning Tree Protocol
Hi:
I have designed my network as Follows:
Cisco Catalyst 3750G Stack as the Core Switches
Cisco ESW 500 Switches as the Edge switches
I am trying to configure Spanning tree on my network with The Core Switches as the root. But i am having a problem with that.
I set the Catalyst 3750 as the root Bridge for all Vlans. But i am having a hard time to configure that on the ESW 500 Switches, as there is no place to configure Per VLAN spanning tree.
Once I configure trunk Ports between the Core and the Edges. The Edge Switches don't consider the the Catalyst 3750G as the root, although it is configured with 0 Periority.
Can you please help me with that?Hi Mohamed,
Thank you for participating in the Small Business support community. My name is Nico Muselle from Cisco Sofia SBSC.
The reason for this not to work is the following : The ESW switches do not support PVST(+) or PVRST like the 3750G does, on the other hand, they support STP, RSTP, and MSTP (MSTP is not supported on the 3750)
So, keeping this in mind, it will not be possible to implement your STP per vlan. In this scenario however, where you set the 3750 as a root bridge for all VLANs, you could easily use RSTP, which is functional on both 3750 and ESW500 switches.
Hope this helps.
Best regards,
Nico Muselle
Sr. Network Engineer - CCNA -
Identifying spanning-tree root switch
Looking at a network with a 6509 at the core running in pvst mode. I think the 6509 is the root switch but need to confirm this.
Show spanning-tree gives a bridge id and a root id. My understanding is that the root id should be the MAC address of the root switch.
However I can't find the MAC address given as the root id in the 6509s mac address table, nor in the access switches mac address tables.
I'm sure I'm missing something here - any ideas?Hi,
in the output of "show spanning-tree" you should look for a line "This bridge is the root". The output will give you the root id and the bridge id of the switch, where you execute the command.
The output looks like this:
Router# show spanning-tree vlan 200
VLAN0200
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address 00d0.00b8.14c8
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address 00d0.00b8.14c8
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
------------- snip -----------
The MAC used for creating the bridge id is not used for forwarding BPDUs and thus does not show up in the CAM table afaik.
To find the root in a switch network, follow the root ports for a given spanning tree instance.
Hope this helps! Please rate all posts.
Regards, Martin -
I want to change the spanning tree root on several vlans on my network. My question is, will this cause STP to recalculate for the entire network, which can cause the network to slow down or will it only affect the vlans that I am changing? I want to make sure I am not going to impact anything on the network.
When executed properly, this will only affect the vlans that you wish to change. Use the folllowing command to change spanning tree prio on a vlan:
spanning-tree vlan xx priority 4096 (or a multiple of 4096 for less priority)
Be aware that there is always a risk of unexpected disruptions when you do this. The vlans that you change may still carry user traffic altough there are no users on it. If your topology and traffic flow are not exactly as you assume they are, more vlans may be affected. It is therefore not advisable to alter this setting during peak-hours.
Regards,
Leo -
I have a vSphere 5.5 install and I'm in the process of a network upgrade in preparation for a VOIP implementation. The Switch hardware I'm using is a stack of Cisco 3850 Layer 3 switches and I've been going in circles on getting vlan traffic to work correctly. Hopefully someone can point me in the right direction.
I have one NIC connected to the switch (10GB fiber) that will handle all traffic for the esxi host (except for management). VLAN ID is set to None (0) and load balancing is set to Route based on originating virtual port.
I have 2 subnets, 10.1.0.0/16 (data & management, VLAN 1) and 10.10.1.0/24 (Voice, VLAN 10)
On the host I have a Win 2012 R2 server that will be a VOIP PBX host. It must be able to communicate with the IP phones (VLAN 10) and other servers (VLAN 1).
The switches will do the intervlan routing.
Finally my question - Can anyone give me some hints on how to set up the interface on the Cisco for the 10GB fiber connection from my host? Actual port settings would be extremely helpful. Anything I'm doing at the vmware end that I should be doing differently?In case anyone comes across this in a search, here's what I ended up with, 1st the Cisco switch:
switchport trunk allowed vlan 1,10
switchport mode trunk
switchport nonegotiate
switchport voice vlan 10
macro description cisco-switch
spanning-tree portfast
spanning-tree link-type point-to-point
The virtual switch I set to all vlan IDs and Route based on originating virtual port. -
SGE2010 switches, VLAN's and a blocked port in spanning-tree
Folks,
I have 2 switch groups.
2 SGE2010's with VLAN's defined as 10,20 and 30
Vlan 10 is the management VLAN, and it uplinks to our border router.
Vlan 20 is the workstation VLAN, and all workstations point to the switch as their default GW
Vlan 30 is the ip phone VLAN, and all phones use this as their gateway.
I would like to put a LAG between said switches, we have some servers on the ip phone switch that need to be accessed by the workstation clients, and the single 100mb link through the router is probably not going to be enough.
As I understand it, because the switches have different networks on them, a simple lag will not work. I did create a lag, and assign ip addresses to each side, however in that mode, it doesn't appear I can block vlan 10 from transiting the LAG, and with out that block I will end up with a logical loop, and spanning-tree will block one of the uplinks, or the LAG itself.
I have attached an image with a diagram of our current set up.
Any help/advice would be much appreciated.Tom,
I remember our conversation a few weeks ago. I did not get a chance to have a go at MSTP, mainly because I have no expierence with it, and looking at the configuration properities, it looks a little daunting.
It has also been a very busy few weeks with the deployment of 200+ phones across several sites, and the system is functioning great with out the LAG trunk, I am just trying to plan for the future.
I made a few postings a few weeks ago, one here and one on the Cisco forums on reddit, and a user there gave me some advice I have been unable to make work (I think it's just wrong), but I would love to go this route if it is in fact possible.
Here is the thread : http://www.reddit.com/r/Cisco/comments/x91tc/vlan_trunks_spanning_tree_and_a_port_blocked/c5kskch
This user implies it's possible to block a VLAN across the LAG which would end the logical loop problems.
It looks like his advice is to make the LAG into a trunk, and then block specific VLAN's from transiting it, but in trunk mode, I can't assign it an IP, so I am sorta wondering how exactly you transport packets across it.
Can you confirm that his advice is in fact incorrect?
If MSTP is my only route, then I suppose it's time to dig into the docs and see If I cant get it up and running. -
E100 & E1000 Spanning tree and VLAN reuse
I have a situations where I have two e series cards configured as single card ether-switches in the same chassis. One is an E100 and the other is an E1000. I have spanning tree enabled on all the transport circuit built to these cards. There is no STS connectivity between these cards.
I am reusing a few VLANs between the cards and the cards appear to be sharing spanning tree topology information. Has anyone had similar experiences reusing VLANs and discovered a work around for this? The 15454 documentation is not very descriptive of this situation and lacks detailed STP info as on would expect to be accessible from a Cisco switch.
Thanks,
KenI'm not so sure that singlecard/multicard mode has anything to do with STP on E-Series cards. From the book Optical Network Design and Implementation:
"It is important to remember that in the case of the E-Series cards, the Timing and Control 2 (TCC2) common card actually runs the spanning-tree engine with a single instance of STP per node. Each E-Series card plugged into the chassis maintains only a copy of its Layer 2 forwarding table. In the case of ML-Series cards, however, the individual cards maintain copies of the Layer 2 forwarding table and they run an instance of STP." ... "From an STP perspective, however, the entire ONS node is perceived as a single bridge, even though it might contain multiple E-Series cards. For ML-Series cards, however, each card is accounted for as a discrete bridge, and STP uses each and every ML-Series card for its STP computation." -
Hi,
I need an answer to this puzzling scenerio i have been asked to work with.I have two vlans with about 10 switches on each end and there is a link switch that has a connection to both sides of the VLAN. I have been asked to create a singular spanning tree for the entire scenerio. how can i go about this.
please i am awaiting the opinions of anyone knowledgable in this line. thanks.Hi, I agree you can config MST on your router to reduce the number of spanning tree instances runing on the switch from one per vlan. You will have to map your vlan range to the MST, useful CLI commands are
spanning-tree mode mst
spanning-tree mst configuration
name (name)
revision( revision number)
instance (number) vlan (vlan range)
check your config using
show spanning-tree mst configuration.
Hope thsi will hlep you get started.
DW
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