Sim, voc� ter� que ter um m�dulo de roteamento no seu Switch.
Sobre ISL, trata-se de um protocolo de Trunking propriet�rio da Cisco.
A t�tulo conceitual, recomendo a leitura do Q&A abaixo. Pelas suas
perguntas, eu acho que voc� vai interessar-se:
"Q: I want to connect a 3524 switch to an existing switched network.
The main switch is a Catalyst 6509, and its GBIC has been used to
connect to the 4006 switch. I've decided to use one of the ports in
module 3 of the Cat6509. I used a crossover category 5 cable to
connect the fast Ethernet ports: Port 3/15 on the Cat6509 and 0/1 on
the Cat3524. Both ports were set to 100mb, full duplex, the same admin
VLAN 1, the same VTP domain, same vtp mode (Server mode). Both ports'
trunking mode and encapsulation were set to nonegotiate and dot1q,
respectively.
The problem: When I ping any IP address in the network from the 3524
console I get 0/5 success rate. No traffic is passing between the
switches.
I wonder if the 3524 fast Ethernet port has trunking capabilities. I
did a show port capabilities on the 3524 console, but didn't get
enough info. Please help me to resolve this problem.
_____________________________________________________________
A: A complicated scenario! Let's step back a little bit (and help
bring everyone else up to speed).
Trunks are used to tie switches together, and pass information for
multiple VLANs through a Layer 2 network. VLANs are various ports on a
switch (or multiple switches) that act as a Virtual LAN, even though
they're distributed throughout a network.
Switches, being a Layer 2 device, don't inherently have the
capabilities of making judgments about network addressing. So as they
trunk various frames among themselves, there must be a router
someplace to make Layer 3 (routing) decisions.
When you connect multiple switches through trunks, in order to pass
multiple VLANs of information along, you need to establish some
hierarchy of communications so that all switches agree with the
information they're passing. This is done through the trunking
protocol and through VTP (Virtual Trunking Protocol) domains.
So, I hope that while I explain the basics here, I'll address your
troubleshooting question as well!
To begin with, all switches should share the same trunking protocol.
If all switches are Cisco, then we can choose ISL as a trunking
encapsulation type. If all switches aren't Cisco, or if we want to
allow other switches in the future, we may choose the IEEE option,
802.1q trunking.
Now, as a side note, you mentioned that you have a Catalyst 4000 in
the mix. The Cisco 4000 switch *only* supports 802.1q trunking, so ISL
isn't an option there.
So we've decided that 802.1q is going to be the trunking protocol (as
you mentioned). In all commands, this is known in the Cisco world as
"dot1q" encapsulation. Next, we need to turn the trunking on. Well,
OK... First thing we should do is make sure we *can* turn the trunking
on!
Not all modules on a 6500 series switch support trunking. In order to
find out whether a particular port does or not, simply type:
show port capabilities 3/15
On your 6509, you should see some output similar to this:
Sa> (enable) show port capabilities 3/15
Model WS-X5530
Port 1/1
Type 1000BaseSX
Speed 1000
Duplex full
Trunk encap type 802.1Q,ISL
Trunk mode on,off,desirable,auto,nonegotiate
Channel no
Broadcast suppression percentage(0-100)
Flow control receive-(off,on,desired), send-(off,on,desired)
Security no
Membership static
Fast start yes
Rewrite no
The important part is the line beginning with "trunk encap type",
which shows the modes that are possible for that particular port. If
you don't see any reference to trunking, then you can't trunk on that
port.
On your 2900XL and 3500XL switches (XL being important!), any
100Base-TX or gigabit Ethernet port can serve as a trunk port for ISL
or IEEE802.1q encapsulation.
On the 5000/6000 switches, the command you likely want to set up the
trunk is:
set trunk 3/15 on dot1q
Then
show trunk
to verify configuration.
On the 2900XL and 3500XL switches, the commands are:
interface fa0/1
switchport mode trunk
switchport trunk encapsulation dot1q
Then
show interface fa0/1 switchport
to verify configuration.
Regarding the VTP setup, you mentioned that both switches were set to
"server" mode. I would have to ask whether that is a necessity for
your network. Server mode passes information, but is done on switches
where changes to the VLAN structure will take place. Most often,
distribution-level or access-level switches are set to
vtp client
mode, so they'll receive VTP messages and pass them accordingly, but
will not originate.
If your 3524 is set to server mode, and has a higher revision of the
vtp database than other servers are feeding it, it will ignore the
updates, and potentially can send bad information out to everyone
else. So be careful with this!
On 802.1q trunks, it's important that all involved switches share the
same management VLAN (the untagged one); so the IPs should be in the
same subnet (and the same gateway...).
And, since we're having so much fun troubleshooting the complex
scenario here, I'll take the time to point out that 80 percent of all
connectivity problems occur at the physical layer -- especially if
we're at the point where all configuration is, indeed, accurate, but
no traffic at all (no cdp either?) is passing. Switch cables out, take
a cable tester to the cable, or whatever method you want to do to
verify connectivity.
It's possible to get link lights on both ends without being able to
actually pass traffic back and forth.
Last, an extra note when dealing with 6500s and 4000s working
together. Turn off VTP pruning. There are some technical issues that
cause a lot of messages to be sent between switches andincrease the
instability. (Go figure.)
I hope these little tidbits give you the insight you need to
troubleshoot the problem!"
-----Original Message-----
From: Lindolfo Alves [mailto:[EMAIL PROTECTED]]
Sent: segunda-feira, 29 de janeiro de 2001 10:34
To: Lista de Discuss�o Rede Wan
Subject: [redewan] Vlans Catalyst 4000.
Lista de Discuss�o Rede Wan - http://www.networkdesigners.com.br
Ol� Pessoal,
Estou com uma duvida em rela��o a cria��o de Vlans aqui no
Catalyst
4000.
No meu Switch atual (Cajun) ele tem como vc configurar interfaces
de
Vlans. S� que no Catalyst n�o estou achando uma maneira de se fazer
isto.
Andei pesquisando e vi que para se fazer isto tem que se ter um
Switch/Router � verdade?
Bom sei que existe um m�todo de se fazer um tal de Trunking usando
o meu
router. Gostaria de saber se algu�m da lista usa isto?
Tem tb um tal de ISL, algu�m daqui usa isto??
Abra�o a todos,
Lindolfo Alves.
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