InterVlan Routing

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Jul 12th, 2007
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Hi,

I have 2 3560 switches connected to each other in a closed network. I've created 10 active VLANs. I want VLAN4, VLAN5, and VLAN6 to talk to each other.

Could you please help me with the intervlan configuration in order the 3 VLANs will be able to talk.

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Edison Ortiz Thu, 07/12/2007 - 07:36
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Have you created a Switch Virtual Interface (SVI) for each VLAN ?


On a switch, you create a VLAN (layer2) and you need to associate that VLAN to a SVI.


For instance, Layer2:


(config)#vlan 4


Layer 3:


(config)#interface vlan 4

(config-if)#ip address 10.4.1.1 255.255.255.0


Do the same for remaining VLANs. Keep in mind, 3560 come with routing disabled, so you need to type


(config)#ip routing


This will enable inter-vlan routing and allows you to configure dynamic routing protocols between the 2 switches, which brings me to the next question, what kind of dynamic routing protocol are you planning to run ?



valides007 Thu, 07/12/2007 - 08:46
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well i'm running rip..

I did the SVI, it's still not working though.

i have a workstation on vlan 4 that can't talk to a system manager on vlan 5. what am i missing here?


Edison Ortiz Thu, 07/12/2007 - 09:16
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Let's see the output from typing:


show ip route from the switch.


Also, is the source and destination on the same switch ?


Verify the workstation and system manager's default gateway, they should point to the IP address of their respective SVIs.


valides007 Thu, 07/12/2007 - 09:26
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the source and destination are on the same switch.

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, E - EGP

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


10.0.0.0/24 is subnetted, 5 subnets

C 10.1.40.0 is directly connected, Vlan4

C 10.1.60.0 is directly connected, Vlan6

C 10.1.50.0 is directly connected, Vlan5

C 10.1.110.0 is directly connected, Vlan1

C 10.1.100.0 is directly connected, Vlan10


Edison Ortiz Thu, 07/12/2007 - 09:32
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Let's see the ipconfig /all from the source and destination workstation and a show arp from the switch

sundar.palaniappan Thu, 07/12/2007 - 09:34
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You can do this without any routing protocol.


Configure all the layer 2 VLANs in both switches and configure SVIs for the 3 VLANs that you want to do inter-vlan routing on BOTH switches. Configure the link between both switches as a trunk port. Of course, enable IP routing on both switches.


Here's a small example:


Switch_1:


vlan 4

name test


int vlan 4

ip add 172.16.4.1 255.255.255.0



Switch_2:


vlan 4

name test


int vlan 4

ip add 172.16.4.2 255.255.255.0


Actually, if you configure the link between the two switches as a trunk you don't even need to configure SVI on both switches but choose the option you desire.



HTH


Sundar



valides007 Thu, 07/12/2007 - 09:46
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here are the show arp and show ip int br:


MS&F#show arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 10.1.40.1 - 001b.5440.7543 ARPA Vlan4

Internet 10.1.60.1 - 001b.5440.7545 ARPA Vlan6

Internet 10.1.50.1 - 001b.5440.7544 ARPA Vlan5

Internet 10.1.110.5 75 001b.5384.a240 ARPA Vlan1

Internet 10.1.110.4 76 001b.5384.8bc0 ARPA Vlan1

Internet 10.1.110.6 62 001b.5354.fc40 ARPA Vlan1

Internet 10.1.110.3 61 001b.5384.a4c0 ARPA Vlan1

Internet 10.1.110.2 - 001b.5440.7540 ARPA Vlan1

Internet 10.1.100.1 - 001b.5440.7549 ARPA Vlan10

Internet 10.1.110.20 0 0017.a4dd.38fd ARPA Vlan1

Internet 10.1.60.150 15 0001.292c.369a ARPA Vlan6


MS&F#show ip int br

Interface IP-Address OK? Method Status Protocol

Vlan1 10.1.110.2 YES NVRAM up up

Vlan2 unassigned YES manual up up

Vlan3 unassigned YES manual up up

Vlan4 10.1.40.1 YES manual up up

Vlan5 10.1.50.1 YES manual up up

Vlan6 10.1.60.1 YES manual up up

Vlan7 unassigned YES manual up up

Vlan8 unassigned YES manual up up

Vlan9 unassigned YES manual up up

Vlan10 10.1.100.1 YES manual up up



Edison Ortiz Thu, 07/12/2007 - 09:49
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I see several hosts on Vlan 1 and one host on Vlan 6, can you ping these hosts from the switch ?


You need to verify these hosts have the correct default gateway. For host on Vlan 6, the default gateway should be 10.1.60.1 and for hosts on Vlan 1, the default gateway should be 10.1.110.2

valides007 Thu, 07/12/2007 - 10:09
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the several hosts are 3560 switches connected to this switch. the network is based on 5 switches connected through a ring. I'm able to ping to all of them.


i realized that the system manager (10.1.40.100)that is connected to the switch wasn't shown when i did show arp. does this explain anything?

Edison Ortiz Thu, 07/12/2007 - 10:18
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Try pinging 10.1.40.100 from the switch holding the IP 10.1.40.1


Then it should show up in the arp table.


You should also receive a reply from the device.

shivlu jain Thu, 07/12/2007 - 11:36
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hi

simply create

ip routing

int vlan 4

ip address <>

int vlan 5

ip address <>

int vlan 6

ip address <>

After that you can see you are getting the routes of these vlans by C

sh ip route


Hope this will help you .


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