Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Cisco > turn part of the cisco switch into a plain switch

Reply
Thread Tools

turn part of the cisco switch into a plain switch

 
 
a
Guest
Posts: n/a
 
      02-13-2007
Hi

I would like to turn a few switchports of my 3560 into a completely separate
dummy plain switch. Is it possible?
I have configured a few ports to be no access vlan. Devices connected in
these ports are able to ping each other.
However, devices connected in these ports are not able to ping the devices
connected in ports that have assigned vlans. This makes the switch
configuration not equivalent to a separate dummy plain switch. How to make
the separation possible?

Thanks




 
Reply With Quote
 
 
 
 
BernieM
Guest
Posts: n/a
 
      02-13-2007

"a" <(E-Mail Removed)> wrote in message news:KTcAh.962240$R63.824699@pd7urf1no...
> Hi
>
> I would like to turn a few switchports of my 3560 into a completely
> separate
> dummy plain switch. Is it possible?
> I have configured a few ports to be no access vlan. Devices connected in
> these ports are able to ping each other.
> However, devices connected in these ports are not able to ping the devices
> connected in ports that have assigned vlans. This makes the switch
> configuration not equivalent to a separate dummy plain switch. How to make
> the separation possible?
>
> Thanks
>
>


Ports configured as access ports default to vlan 1 unless they have been
assigned to another vlan. Configuring "no switchport access vlan" puts then
into the default vlan ... vlan 1. Hosts connected to those ports can ping
each other because they are in the same vlan and cannot ping hosts in other
vlans ... as you would expect from a 'dummy plain sitch'.

What switching rules do you expect?

BernieM




 
Reply With Quote
 
 
 
 
a
Guest
Posts: n/a
 
      02-13-2007

"BernieM" <(E-Mail Removed)> 撰寫於郵件新聞
:45d15e4e$0$34578$(E-Mail Removed)...
>
> "a" <(E-Mail Removed)> wrote in message

news:KTcAh.962240$R63.824699@pd7urf1no...
> > Hi
> >
> > I would like to turn a few switchports of my 3560 into a completely
> > separate
> > dummy plain switch. Is it possible?
> > I have configured a few ports to be no access vlan. Devices connected in
> > these ports are able to ping each other.
> > However, devices connected in these ports are not able to ping the

devices
> > connected in ports that have assigned vlans. This makes the switch
> > configuration not equivalent to a separate dummy plain switch. How to

make
> > the separation possible?
> >
> > Thanks
> >
> >

>
> Ports configured as access ports default to vlan 1 unless they have been
> assigned to another vlan. Configuring "no switchport access vlan" puts

then
> into the default vlan ... vlan 1. Hosts connected to those ports can ping
> each other because they are in the same vlan and cannot ping hosts in

other
> vlans ... as you would expect from a 'dummy plain sitch'.
>
> What switching rules do you expect?
>
> BernieM
>


Hi Bernie
Thanks for your reply.
But I have used no access vlan 1 for that switchport, is it still in vlan 1?
If the devices are in VLAN, then it is not a dummy switch.
It is because the packet will first try to find its default VLAN interface.
A dummy switch is just like a physical layer switch with CLI control. Just a
little bit more than a piece of cable.
Is it possible?
Thanks




 
Reply With Quote
 
JF Mezei
Guest
Posts: n/a
 
      02-13-2007
a wrote:
> But I have used no access vlan 1 for that switchport, is it still in vlan 1?
> If the devices are in VLAN, then it is not a dummy switch.


You want say 4 ports to act as if they were on their own independant dummy
switch, right ?

Then you put those 4 ports into their own vlan (say vlan 7). Then any/all
traffic that is sent into any of those 4 ports will only ever go to those 4
ports, just like it was in its own switch.

Broadcasts sent by a device connected to one of those 4 ports will only go
to the other 3 ports on that VLAN.

> A dummy switch is just like a physical layer switch with CLI control.


The would be a hub then.

A hub transmits all information from all ports to all ports.
A switch learns the ethernet addresses of devices connected to each port,
so a unicast to a known ethernet address gets sent to only that port.


I am not certain you could turn all 4 ports into a "hub". But you can make
one port listen in on the remaining 3 with port mirroring. This way, one
port would see all the traffic sent/received by the other 3 ports. (acting
a bit like a hub).
 
Reply With Quote
 
BernieM
Guest
Posts: n/a
 
      02-13-2007

"a" <(E-Mail Removed)> wrote in message news:iFeAh.961730$5R2.878555@pd7urf3no...
>
> "BernieM" <(E-Mail Removed)> 撰寫於郵件新聞
> :45d15e4e$0$34578$(E-Mail Removed)...
>>
>> "a" <(E-Mail Removed)> wrote in message

> news:KTcAh.962240$R63.824699@pd7urf1no...
>> > Hi
>> >
>> > I would like to turn a few switchports of my 3560 into a completely
>> > separate
>> > dummy plain switch. Is it possible?
>> > I have configured a few ports to be no access vlan. Devices connected
>> > in
>> > these ports are able to ping each other.
>> > However, devices connected in these ports are not able to ping the

> devices
>> > connected in ports that have assigned vlans. This makes the switch
>> > configuration not equivalent to a separate dummy plain switch. How to

> make
>> > the separation possible?
>> >
>> > Thanks
>> >
>> >

>>
>> Ports configured as access ports default to vlan 1 unless they have been
>> assigned to another vlan. Configuring "no switchport access vlan" puts

> then
>> into the default vlan ... vlan 1. Hosts connected to those ports can
>> ping
>> each other because they are in the same vlan and cannot ping hosts in

> other
>> vlans ... as you would expect from a 'dummy plain sitch'.
>>
>> What switching rules do you expect?
>>
>> BernieM
>>

>
> Hi Bernie
> Thanks for your reply.
> But I have used no access vlan 1 for that switchport, is it still in vlan
> 1?
> If the devices are in VLAN, then it is not a dummy switch.
> It is because the packet will first try to find its default VLAN
> interface.
> A dummy switch is just like a physical layer switch with CLI control. Just
> a
> little bit more than a piece of cable.
> Is it possible?
> Thanks
>
>
>


You may have used "no access vlan 1" but does that appear in the config? A
switchport by default is in vlan 1 but "switchport access vlan 1" is one of
those default settings that doesn't appear when you do a "show run".

What do you mean by a dummy switch. By default all ports on a switch are in
the same vlan but not 'on the same piece of wire'. As JF Mezei explained
that's the difference between a switch and a hub. For the switch to act
like a hub you'd have to disable the 'mac-address table' function so all
packets get transmitted out all ports. Is this what you're expecting?

What do you mean by "the packet will first try to find its default VLAN
interface"? Frames coming from the servers and frames coming from the
switch, on an access port, are not vlan tagged.

BernieM


 
Reply With Quote
 
mprasad079 mprasad079 is offline
Junior Member
Join Date: Dec 2012
Posts: 12
 
      12-23-2012
If you dont what to ping each other or specific ping is required, use PVLAN concept. ISP does use this concept in there domain.
 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Turn a Cisco Router into a DNS server jsh3323 Cisco 3 03-27-2006 04:55 PM
Part Number of Cisco 3552 SMI Switch Sabya Cisco 4 10-17-2005 03:43 PM
[meta] Why do some of my posts turn into weird multi-part mimedocuments? David A. Black Ruby 4 10-11-2005 06:14 PM
How to Display get text/plain body part from the message??? sgane Java 1 10-11-2004 04:08 PM
turn quotes into &quot; and apostrophes into &apos; Eric Osman Javascript 2 04-14-2004 03:51 PM



Advertisments