VLAN Aggregation

In RFC 3069, Table 2, followed by Section 6, are what really matters.

It's obvious that you can aggregate IP addressed among LANs. You do this anytime you connect two Ethernet hosts to an Ethernet layer 2 switch (i.e. bridge), and assign those two to the same IP subnet. So it should be clear that the same can be done between VLANs.

RFC 3069 says that implementation details are not considered in the RFC. Seems to me, you can create a single spanning tree, then use IP addresses to determine who the various members are in each VLAN. This is a valid way to create VLANs.

Also, pay attention to this text in Section 6:

"That is, when an address or range of addresses is allocated to a given sub-VLAN, reception of IP or ARP packets on a sub-VLAN with a source IP address that isn't allocated to the sub-VLAN should be discarded, ..."

So, the way I'd set this up, a single broadcast domain, and only IP addresses used to differentiate between VLANs.

Bert

my query =A0and

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Hello Sir

as u write

Seems to me, you can create a single spanning tree, then use IP addresses to determine who the various members are in each VLAN. This is a valid way to create VLANs.

can u plz define how by creating a single spanning tree , and using IP address to determine who the various members are in each vlan.

Vikrant

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Hello Sir

i 've one more question related to promiscuous port as i know the defination of this promiscuous port .. it can talk to all other types of ports

But my question is how we make a port promiscuous means becaming a port promiscuous is only done by when the switch controller gives the capability for promiscuous or making a port promiscuous is done by something else

please clearify this .....

Thanks in advance

Vikrant

Whether a port is promiscuous or not is controlled on the switch. That control may be by switch software or by switch hardware.

Making a port promiscuous is *not* done by the contents of any data packet. You cannot, for example, set a particular bit in the layer 2 headers to signal to the switch that it needs to switch into promiscuous mode.

There is no requirement that any switch (of any Layer of operation) support promiscuous ports.

members are in

We've been throught this, haven't we? A single spanning tree can be used in 802.1Q VLANs. It might not be the most efficient tree for each of the VLANs, but it has to work. After all, the spanning tree does join together all of the switches in the mesh, with no loops. So the edge ports of any switch can be made to belong to any VLAN defined in that mesh.

Bert

I should have added, of course, that if this is true with 802.1Q, why should it not also apply to other types of VLANs?

Bert

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Ok Sir,

I m thinking some about a promiscuous port .... i m writing it you please tell me is it correct or not

I think when we set some ports or any one port to primary vlan (default vlan 1) and allocate a l3 device to this port then this port or ports are termed as promiscuous port....

Is it correct................

regards

Vikrant

What are you asking?

Are you asking what a promiscuous port is, or are you asking how the existence of VLANs in a given L2 network affects the definition of promiscuous port?

Bert

I just did a quick search under "promiscuous port," as opposed to the more general "promiscuous mode," and came up with this definition:

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39.0 The following are true about PVLANs:

1. There are three types of private VLAN ports: promiscuous, isolated, and community.

1.1 Promiscuous port: A promiscuous port communicates with all other PVLAN ports, and is the port typically used to communicate with external routers, servers, administrative workstations, etc. [ ... ]

1. In a PVLAN, promiscuous ports are called the primary VLAN, while community and isolated ports are called secondary VLANs.

2. A PVLAN will only have one primary VLAN, but may have several secondary VLANS.

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Bert

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so by setting a port to PVLAN , then this port is known as promiscuous port ????

Vikrant

I'm not sure what you're asking. Are you asking whether all ports in a port based VLAN are promiscuous ports? Where would you get that interpretation?

Bert

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i m saying all ports which are given to primary vlan ( by default is vlan 1) are known as promiscuous ports. is'nt it ????

=2E...

Well, you know, PVLAN can mean "port based," or "private," or who knows what else.

The answer to your question depends on the switch manufacturer, but most likely the answer is yes. It all depends what a particular vendor defines as "primary VLAN." Or what the purpose of this "primary VLAN" is.

See if you can find any reference to "primary VLAN" or "promiscuous port" in IEEE 802.1Q.

Bert