Hi Fugazz, Thank You for quick response. Much appreciated.
Yes, you made it clear. In my case one end Cisco 3750 and other end Aurba os 16.6 so not sure about creating l3 portchannel. If you know this or find something, please let me know. Thank you again.
Hello Nityananad
Kudos to @fugazz for his explanation, clear, comprehensive and correct! As for connecting a 3750 to an Aruba device it is possible to create a port channel. You can do this either by statically configuring it on both ends or by using the Link Aggregation Control Protocol (LACP) to negotiate aggregation, which is an open protocol supported by Cisco and many other vendors. Donāt use PAgP as this is Cisco proprietary.
You can find out more about link aggregation at the lesson posted by @fugazz.
I hope this has been helpful!
Laz
Iām trying to configure a 2950T-24 in packet tracer and when I try to assign fa0/1 an ip address I keep gettting:
North_Switch(config-if)#ip address 192.168.4.3 255.255.255.0
^
% Invalid input detected at '^' marker.
The config is below. Any ideas? Iāve tried āip routingā no switch port (in config mode, per google) no luck.
North_Switch#sh run
Building configuration...
Current configuration : 1447 bytes
!
version 12.1
no service timestamps log datetime msec
no service timestamps debug datetime msec
service password-encryption
!
hostname North_Switch
!
enable secret 5 $1$mERr$.mZUxVw4tp.fz.HSTl9q3/
enable password 7 08314D5D1A0E0A05165A
!
!
!
no ip domain-lookup
!
!
spanning-tree mode pvst
spanning-tree extend system-id
!
interface FastEthernet0/1
description connection to north_host1
duplex half
speed 10
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
North_Switch#config t
Enter configuration commands, one per line. End with CNTL/Z.
North_Switch(config)#int fa0/1
North_Switch(config-if)#ip address 192.168.4.3 255.255.255.0
^
% Invalid input detected at '^' marker.Hello David
The reason youāre getting the error for this command is because the specific switch is a layer 2 switch. This means that its ports cannot operate any layer 3 mechanisms or configurations, therefore they cannot be assigned an IP address. A layer 2 switch can only have an IP address assigned to its VLAN interface more correctly referred to as a Switched Virtual Interface (SVI). In order to assign an IP address to an interface, you require a Layer 3 switch where you can convert a switchport to a routed port and assign the IP address. Or of course, if you use a router, which can have its ports assigned an IP address.
I hope this has been helpful!
Laz
Hi,
I have Cisco Catalyst 3650 switches. I would like to find out how to configure hosts in VLAN 10 & VLAN 20 both talk to VLAN 50ās hosts, but not between each other (VLAN 10 & VLAN 20). If you have video or discussion about it, please let me know. Thank you for your help.
Hello Phong
If you have various hosts on different VLANs on a Layer 3 switch, these hosts will automatically be able to communicate with each other through InterVLAN routing. If however you want to block certain communications between them, then you can use access lists to do so. Take a look at these two lessons. They involve access lists on routers, but the concept is the same for Layer 3 switches:
I hope this has been helpful!
Laz
Why do you have to assign the vlan for an SVI on an access or trunk port? isnāt a SVI a layer 3 port?
It would seem like you should be able to connect to an SVI just like a router port. What is the point of having that random access port up or an allowed vlan over a trunk when you have an SVI(layer 3 port) to let the traffic in? I have done a good bit of googling, and I am honestly not sure where to look.
Hello Justin
When you have a L3 switch, you have the following two options for creating routed interfaces:
no switchport command, and then assign an IP address to the port. This will actually make the physical port function like the port of a router, with an IP address and subnet mask on the interface itself.I hope this has been helpful!
Laz
My question is regarding inter-vlan routing. The short, do all L2 and L3 switches need svi to have a svi with the appropriate vlan, ip address and vlan for inter vlan routing to work? In a three tier Cisco networking framework, Can the access switch have the vlan(s) configured and the end device in the vlan without a svi and up address? Will the following scenario work?
L3
Vlan 10, Interface Vlan 10 - 192.168.10.2/24
Vlan 20, Interface Vlan 20 - 192.168.20.2/24
Trunk between L2 and L3 switch
IP routing is enabled
L2
Vlan 10, interface vlan 10 no IP address
Vlan 20, interface vlan 20 no IP address
Truck between L2 and L3 switch
Pc in vlan 10
Pc in vlan 20
Pc (192.168.10.6) on vlan 10 with the default gateway pointing to 192.168.10.2
Pc (192.168.20.5) on vlan 20 with the default gateway pointing to 192.168.20.2
Hello Derrick
Your description of how to create such a network is absolutely correct. Iāve created a topology with the information you provided:
The result is, when PC1 wants to communicate with PC2, the traffic will:
This is very similar to Router on a Stick, where instead of an L3 switch, you have a router with subinterfaces, one for each VLAN on the trunk.
So for the L2, you donāt need to configure SVIs with IP addresses. The only reason you would do this is to have access to the switch itself via the network for CLI access and configuration. But L2 switches with SVIs wonāt route traffic between VLANs.
I hope this has been helpful!
Laz
Good afternoon,
Iām trying to configure two PCs to be able to ping each other. After setup Iām unable to get them to ping each other.
Here is my setup, PC1 (ā¦155.101) is directly connected to the core layer 3 switch. Itās port has been configured and placed into vlan 1401 with the following commands switchport access vlan 1401, switchport mode access.
PC2 (ā¦155.102) is directly connected to a layer 2 switch. Also, Itās port has been configured and placed into vlan 1401 with the following commands switchport access vlan 1401, switchport mode access.
The Layer 3 switch houses the interface vlan 1401 and its SVI address is ā¦155.65. Between the two switches Vlan 1401 is allowed.
PC1 is able to ping the gateway ā¦155.65. Additionally, to ensure all is well I created a svi on the layer 2 switch and was able to ping PC2. The layer 3 switch is a 3750 and the layer 2 switch is a 3650.
The vlan has been allowed and has not been pruned in the configuration or either switch.
Am I missing anything?
Hello Derrick
To facilitate responding, I have mapped out your topology in the following diagram. I assumed the IP addresses are in the 10.10.155.0/24 subnet:
Now if Fa0/1 interfaces are configured as you state, and the trunk allows the 1401 VLAN, and the PCs are configured with these IP addresses, then they should communicate with each other. Just a note here, that no default gateway should be needed for this communication, since both PCs reside on the same VLAN and in the same subnet. No InterVLAN routing is taking place and thus, configuration of the SVIs is not necessary for connectivity.
Since PC1 can ping the SVI on the core L3 switch, and PC2 can ping the SVI on the L2 switch, then my attention would be brought to the trunk configuration. I suggest you follow this troubleshooting procedure:
If you get the trunk or the access link working between switches, then your topology should function correctly. Let us know your results!
I hope this has been helpful!
Laz
Hi Laz,
In this tutorial you use a line that, if you are having a multiples interface under Vlan use concept of SVI and if having a single interface under Vlan use concept of routed port ::
My question is here that if it is a routed port means switch port then why are you using word of Vlan for this routed port ?
Hi Rene/Laz,
Actually i am unable to get it why are we using SVI concept in this topic and suppose we use this then how can be make this useful for Inter-Vlan routing, could you emphasize it ?
Hello Pradyumna
I understand your confusion. The routed port is configured on Fa0/16 of SW3 and not on SW2. SW2 simply has the Fa0/16 port configured as an access port on VLAN 10, via which all of the hosts in VLAN 10 can reach the default gateway, which is the Fa0/16 port on SW3. Note here that, unlike the previous examples in this lesson, SW2 is a Layer 2 switch, and cannot be configured with a routed port.
The diagram is a little bit misleading because it shows that VLAN 10 of SW2 is only on the ports connected to the hosts, but VLAN 10 is also assigned to the Fa0/16 interface of SW2.
InterVLAN routing will allow hosts connected to access ports on a switch in one VLAN to communicate with hosts on access ports in another VLAN. The SVIs, which are virtual interfaces, act as the router ports between which routing takes place.
I hope this has been helpful!
Laz
Dear Related team of network lessons!
Hello
I didnāt understand truly in Mr. Reneās tutorial the usage of (SIV Autosate exclude command) would you please simply explain it to me that what is the usage of this command?
Thanks in advance for your help and support in this regard.
Regards
Ajmal" Ahmadi"
Hello Ajmal
In order for an SVI to be active (line status up, protocol up), the VLAN that the SVI corresponds to must exist, and there must be at least one access or trunk port that is using the VLAN. Sometimes, you want the SVI to ignore the state of a particular port when deciding to be up or down. So if you issue the autostate exclude command on any interface, the state of that interface will not affect the state of the SVI.
So letās say you have VLAN 10 SVI configured, and you have Fa0/1 and Fa0/2 on VLAN 10. If you enable both Fa0/1 and 0/2 and they are up/up, then the SVI will also be up. If you shut down Fa0/1, the SVI will still be up because Fa0/2 is on VLAN 10 and it is still up.
However, if you use the autostate exclude command on Fa0/2, then the state of this interface will not be examined to determine if the SVI must be up or down. So in this case, if you shutdown Fa0/1, the SVI will go down as well, even though Fa0/2 does exist on VLAN 10 and is still up.
I hope this has been helpful!
Laz
Thanks sir,
For your always awesome response to my questions now I understood.
Regards
Ajmal
Regards,
Ajmal
Hello Ajmal
Based on the addresses that are written in the diagram, the two switches are functioning at layer 2, and all routing is taking place at the router. There is no InterVLAN routing taking place on an L3 switch.
Since you canāt ping from one subnet to the other, I suggest you first verify that the hosts have the IP address of the router as the gateway (each subnet for itself) and make sure that all the hosts can ping their gateway.
Secondly, why do you have a trunks configured between the router and the switches? This would require a router on a stick configuration, but this would also require you to have multiple subinterfaces on the same VLAN, something that is not possible.
Notice that if you have a trunk on these interfaces, then you have two subinterfaces on each of the Fa0/0 and Fa0/1 interfaces, with a total of 4 subinterfaces. But you only have a single subnet appearing for each link.
I would suggest you donāt make these trunks, but make one of them function on VLAN 10 and the other on VLAN 20 and make those router interfaces function as the default gateway for each VLAN.
Try these things out and let us know how you get along!
I hope this has been helpful!
Laz
