VLAN, HSRP & Default Route Configuration

Unanswered Question

Hi All,

I have a confusion as below :-

If I can create VLAN 2-10 in Distribution_1 and Distribution_2, HSRP will be implemented on these both. Again VLAN 10-20 will be created in Distribution_3 and Distribution_4,  HSRP will be implemented on these both. I want all these Distribution switch should be in same VTP domain and VTP mode will be Server for All.

Now, from all the Distribution switch default route will be pointed to Core_1, and the same delafult route will be pointed to Core_2 & Core_3 also along with weighted value, eg as given below:-

From all the Distribution switch the 2no.s default route will be like

ip route 0.0.0.0 0.0.0.0 Core_1

ip route 0.0.0.0 0.0.0.0 Core_2 10

ip route 0.0.0.0 0.0.0.0 Core_3 20

If Core_1 down traffic will move to Core_1 then Core_2 and lastly Core_3. Again all the traffic will come back to Coer_1 when this switch come up. These Core switches also in the same VTP domain with VTP server mode.

Please let me know if it is possible. The Core_3 will be actually a DR site for the exiting DC in the other building near by primary building will be connecetd with Fiber Optic.

I have this problem too.
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Jon Marshall Tue, 05/18/2010 - 01:22

[email protected]

Hi All,

I have a confusion as below :-

If I can create VLAN 2-10 in Distribution_1 and Distribution_2, HSRP will be implemented on these both. Again VLAN 10-20 will be created in Distribution_3 and Distribution_4,  HSRP will be implemented on these both. I want all these Distribution switch should be in same VTP domain and VTP mode will be Server for All.

Now, from all the Distribution switch default route will be pointed to Core_1, and the same delafult route will be pointed to Core_2 & Core_3 also along with weighted value, eg as given below:-

From all the Distribution switch the 2no.s default route will be like

ip route 0.0.0.0 0.0.0.0 Core_1

ip route 0.0.0.0 0.0.0.0 Core_2 10

ip route 0.0.0.0 0.0.0.0 Core_3 20

If Core_1 down traffic will move to Core_1 then Core_2 and lastly Core_3. Again all the traffic will come back to Coer_1 when this switch come up. These Core switches also in the same VTP domain with VTP server mode.

Please let me know if it is possible. The Core_3 will be actually a DR site for the exiting DC in the other building near by primary building will be connecetd with Fiber Optic.

Well yes it's possible although it's not necessarily a good design. It's difficult to say without seeing the whole setup. Also bear in mind that with ethernet you may need to use IP SLA tracking to test the availability of the default route next-hop or you could black hole traffic.

You have 2 pairs of distribution switches are they both in the main site ?

What exactly are you trying to achieve ?

Jon

Hi Jon,

I have attached the Network Arch along with Backbone in the 2nd slide. The requirements are as below :-

1. Main User Base through out the Campus differenr building ( A wing, B Wing, Service, Admin, Etc )

2. I want create individual VLAN in respective Building Distribution Switch.

3. In Admin & Service building there are no Dist switch the distance from Server Room ( Core Switch ) is not very long and the user base is also less comapared to A Wing & B Wing.

4. Now, user asking for a DR site in the same campus ( In Residential Building ) if the Server Room ( Admin 2nd Floor ) got disturbed and the entire Server Room ( Core 1 & 2, Server Farm, Voice etc ) is out of the network.

5. I will make a scaledown DR in that residential bulding with a Single Core switch, and other Server Equipment.

6. All the user traffic will shift to New Core_3 ( DR Site ) from all building.

Please let me know what should be the best practise in this case.

Sujit

Jon Marshall Tue, 05/18/2010 - 02:45

Sujit

Firstly don't use static routes, run a dynamic routing protocol between your core and distribution switches. That way when a switch goes down the route is lost so a different route can be used. If you run static routing then you need to use IP SLA which unnecessarily complicates things.If your network is all Cisco then EIGRP is very easy to setup and configure.

Secondly don't distinguish between core 1 and core 2 in terms of routing ie. you don't need to send everything to core 1 and only then to core 2. You hve 2 equal cost paths so use them.

On the DR switch you can run EIGRP as well and use an offset list so that the routes advertised from the DR switch will not be used unless both core 1 and core 2 have been lost.

If you try and use statics everywhere it will get messy and complicated and there is no need for that.

Jon

Hi Jon,

First of Thanks a Lot for your valuable advise.

Lastly please let me know about the VLAN configuration that asked in my 1st queery.....that is

If I can create VLAN 2-10 in Distribution_1 and Distribution_2, HSRP will be implemented on these both. Again VLAN 10-20 will be created in Distribution_3 and Distribution_4,  HSRP will be implemented on these both. I want all these Distribution switch should be in same VTP domain and VTP mode will be Server for All.

Please advise me, if I should create the VLAN's in Dist switch or all the VLAN in Core only for better mgmt.

Jon Marshall Tue, 05/18/2010 - 03:22

[email protected]

Hi Jon,

First of Thanks a Lot for your valuable advise.

Lastly please let me know about the VLAN configuration that asked in my 1st queery.....that is

If I can create VLAN 2-10 in Distribution_1 and Distribution_2, HSRP will be implemented on these both. Again VLAN 10-20 will be created in Distribution_3 and Distribution_4,  HSRP will be implemented on these both. I want all these Distribution switch should be in same VTP domain and VTP mode will be Server for All.

Please advise me, if I should create the VLAN's in Dist switch or all the VLAN in Core only for better mgmt.

It depends on whether your connections to the core are L2 or L3. If they are L2 then you can have the distribution switches in the same VTP domain. If L3 then you can't, assuming you are not interconnecting dist1/2 to dist3/4.  However there is nothing wrong with having separate VTP domains and if you are using separate distro switches then i would suggest it makes sense to have them on separate VTP domains.

I'm assuming that an access-layer switch either connects to dist1/dist2 or dist3/4 but not to both pairs.

Jon

Hi Jon,

The Bill of Material for Core & Dist Switch as below ( Core_3 is not considered here )

ProductDescriptionReq Qty
Core SwitchWS-C4506-ECat4500 E-Series 6-Slot Chassis, fan, no ps2
PWR-C45-1000ACCatalyst 4500 1000W AC Power Supply (Data Only)2
PWR-C45-1000AC/2Catalyst 4500 1000W AC Power Supply Redundant(Data Only)2
CAB-SABS-C15-INDSABS 164-1 to IEC-C15 India4
S45EIPBK9-12253SGCisco CAT4500E IOS IP BASE SSH2
WS-X45-SUP6-ECatalyst 4500 E-Series Sup 6-E, 2x10GE(X2) w/ Twin Gig2
WS-X4624-SFP-ECatalyst 4500 E-Series 24-Port GE (SFP)2
GLC-SX-MMGE SFP, LC connector SX transceiver48
WS-X4548-GB-RJ45Catalyst 4500 Enhanced 48-Port 10/100/1000 Base-T (RJ-45)2
CVR-X2-SFPCisco TwinGig Converter Module4
CON-CSSPD-C4506ESHARED SUPP SDS Cat4500 E-Series 6-Slot Chassis, fan, no2
Distribution SwitchWS-C3750G-12S-SCatalyst 3750 12 SFP + IPB Image4
CAB-STACK-50CMCisco StackWise 50CM Stacking Cable4
CAB-IND-10A10A Power cable for India4
GLC-SX-MMGE SFP, LC connector SX transceiver48
CON-CSSPD-3750G12SSHARED SUPPORT 8X5XNBD CAT 3750 12 SFP STD MULTILAYER IMG4

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