Intelligent switching technology.

Jul 12, 2005 9 Replies

A couple of years ago I seem to recall reading about some switching technology that switch vendors are/were implementing to prevent switches from forwarding broadcasts out of all of their ports. Essentially the switches learn which devices are connected to which port (they have been doing this forever) and creates some kind of lookup table (port/service etc) that it uses to figure out which ports get which broadcasts.



Does anyone know or remember the common name for this technology?



Any links to relevant documentation would be great too.



Thanks for taking the time to read my post.



Frank Wells


Hi Frank,

You may be referring to "SPAN."

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Sincerely,

Brad Reese BradReese.Com Cisco Repair Service Experts

1293 Hendersonville Road, Suite 17 Asheville, North Carolina USA 28803 Toll Free: 877-549-2680 International: 828-277-7272 Website:
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Thanks for responding Brad. SPAN wasn't what I had in mind. I am referring to a technology which makes switches not act like hubs in that they no longer forward broadcasts through every port.

Switches were originally designed with solving the collision domain problem and they succeeded marvelously. However, a few years later some switch wizards decided they could also solve the broadcast domain problem and thus the created the technology I am trying to explain.

My apologies for not doing a better job of explaning their use in my original post.

hm, maybe you have a 'vlan' in your mind? around this technology some vendors create 'intelligent' procedures to assign dynamically clients/ports to a vlan (e.g. through inspecting arp requests and assign the port the request came in to a special vlan for a certain amount of time).

-gerald

On 13.07.2005 00:10 snipped-for-privacy@hotmail.com wrote

Maybe you are thinking of Vlans? With Vlans the switch only broadcasts to every port in the Vlan.

Arnold

No, Vlan's are not it either but thanks for asking.

Frank,

You may be referring to a Virtual VLAN Switch:

The word "Virtual" in the term "Virtual VLAN Switch" refers to the Switch, not the VLAN.

In other words, the Viadux 5000's Virtual VLAN Switching technology allows the Viadux 5000 to emulate the functionality of multiple VLAN switches, all within a single VLAN switch.

Thus, the "Virtual" refers to the fact that there aren't really multiple physical switches, just a single physical switch.

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Now the next question might be, what are the features and targeted applications for "Virtual VLAN Switching" technology?

The targeted application is broadband service delivery at the edge of service provider networks, typically within a multi-tenant customer building itself, where the service provider is selling Transparent LAN Services (also known as Virtual Leased Line Services, or Site-to-Site Services), as well as Internet Access Services, to various customers in the building.

A Transparent LAN Service is a virtual LAN extension of the customer's LAN, over the service provider network, to another building off the service provider network where a branch of the same customer exists.

A Transparent LAN Service allows the end-customer's remote branch to connect to the end-customer's local branch transparently, making it look just as if everyone in the end-customer's organization was in the same building.

Many customers use VLAN switching in their LANs. To allow LAN-based VLAN switching in a Transparent LAN Service, the customer VLAN tags must either be tunneled, or swapped, when the customer traffic enters the Service Provider network, and then un-tunneled, or swapped back, when the customer traffic leaves the Service Provider network.

If this is not done, then traffic with identical VLAN IDs from different customers will intermingle, causing security and network problems.

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The Viadux 5000 supports LAN-based VLAN switching by tunneling customer VLAN traffic.

It is in the configuration and management of these VLAN tunnels that the features of Virtual VLAN Switch technology are most frequently used.

Specifically, because each customer VLAN tunnel can be assigned to a different VLAN switch inside the 5000, trunk 802.1Q tag values can be re-used on different trunk ports, allowing the solution to scale beyond the 4096 tunnels that can be supported with the range of 802.1Q addresses.

Also, each VLAN switch can be configured with a different VLAN protocol ID value, which is useful when connecting to VLAN tunnel switches from different manufacturers at remote locations (different VLAN tunnel switch manufacturers sometimes use different VLAN protocol ID values, and the VLAN protocol ID settings are not always programmable).

Lastly, within each VLAN switch in the Viadux 5000, tunneling can be setup to occur on the WAN egress port, allowing customers who are connected locally to multiple ports on the 5000 to switch customer VLAN-tagged traffic between local ports, without this traffic having to be tunneled out the WAN, consuming bandwidth from a many-times bandwidth constricted uplink.

Virtual VLAN Switch Services Diagram:

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As seen from the above discussion, the Viadux 5000 is targeted towards use in service provider networks that are transporting the traffic of multiple end-customers.

There are enterprise applications where the 5000 can also be used, but typically Virtual VLAN Switch technology features are not used in enterprise deployments end-customers.

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Please feel free to contact Reggie Grant if you have any additional questions.

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Brad Reese BradReese.Com eBay Cisco Repair
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Frank,

An additional note.

Spoke earlier today with Vicki Marion, President and CEO of Viadux, Inc. in San Diego, California.

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After 8 years in business Viadux is finally closing down rather than going back to seek further investor / venture funding.

So all Viadux "Virtual VLAN Switch" technology is for sale.

Brad Reese

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Yes, they did.

They are called routers!!!! Bur they were designed even before the switches. Some clever guys came with the idea of "encapsulate" the routing intelligence in an ASIC, so, they "invented" the L3 Switches!!.

Just Kidding.

In article , BradReeseCom wrote: :You may be referring to a Virtual VLAN Switch:

:Many customers use VLAN switching in their LANs. To allow LAN-based :VLAN switching in a Transparent LAN Service, the customer VLAN tags :must either be tunneled, or swapped, when the customer traffic enters :the Service Provider network, and then un-tunneled, or swapped back, :when the customer traffic leaves the Service Provider network.

:If this is not done, then traffic with identical VLAN IDs from :different customers will intermingle, causing security and network :problems.

That sounds like the issue that Cisco deals with via the "Tunnel In Tunnel" or "Private VLAN" feature.

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