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Ethernet Switches & Routers

Video: Configuring Dual-mode Ports

by DennisMSmith on ‎06-20-2016 07:53 AM - edited on ‎03-20-2017 09:23 AM by Community Manager (2,723 Views)

This video will explain how to configure dual-mode ports on Brocade campus switches.



Video Transcript:


0:04 – This is the Brocade campus feature explainer series I'm Terry Henry today we're

0:09 – going to talk about dual mode ports so a dual-mode port is a port that has the

0:13 – ability to send tagged and untagged frames at the same time

0:17 – so what do we use this for well the largest used by far is VoIP phone so on

0:23 – most if not all VoIP phones you've got two ports so you take tagged traffic which

0:29 – is your phone traffic and untagged traffic which is connects to your pc or whatever

0:35 – device you have connected to the second port of the IP phone and the reason we

0:39 – sent tagged traffic to the phone is because primarily because that's how we send

0:46 – 802.1p QOS bits without it being tagged there's nowhere

0:51 – to write those qos bits and so therefore we have no clue what's going to and from

0:55 – the phone the other uses for it is cisco native VLAN cisco often sends untagged

1:01 – frames for things like PVST plus on an untagged port

1:07 – even on a tagged or what they would call trunk interface and thirdly many access

1:13 – points on the market

1:15 – use tagged and untagged the same time so the untagged would be used for

1:19 – configuration and management and then the tagged would be used for the user SSID’s

1:24 – So a couple of things to keep in mind you can have as many tags vlans on

1:30 – an interface as you want but only one untagged so that will become important in a

1:34 – minute during the configuration and lastly fast port span or the ability to

1:40 – put a port into forwarding mode in four seconds or less as opposed to you know

1:47 – the default of 30 seconds and regular spanning tree is not going to work with

1:52 – dual mode because in order to configure dual-mode you have to have a ---

1:57 – it breaks two rules one is that the port is going to be tagged and the second

2:03 – you're going to learn more than one mac address on that port so it's going to

2:05 – disable fast port span so you should use rapid spanning tree which is it is

2:11 – faster than fast port span anyway so it doesn't utilize fast port span

2:16 – so let's have a look at how we can figure that

2:19 – so we're go into config t so what we're going to do is we're going to create our

2:24 – vlans like usual

2:25 – so we'll create a VLAN 10 and a VLAN 20

2:29 – so if you VLAN10 name is PC and we're going to tag will use with Ethernet

2:40 – 1/1/1 in this example okay and then we are going to create a second vlan for

2:46 – voice will say VLAN 20

2:48 – name voice that the name is optional of course we're going to tag that same

2:55 – interface so I got I just got done telling you that it's going to send

3:01 – tagged and untagged same time however in order to configure dual-mode we need to

3:07 – tag all of the vlans and then the one VLAN that you want untagged you're going to

3:12 – put into dual mode so that so we've got our two vlans created

3:16 – we've tagged the interface out to the to the IP phone and the pc and then lastly

3:21 – we're going to go into the interface itself interface e 1/ 1/1 and we're

3:26 – going to say dual mode so it’s dual-mode and then if you just hit enter here

3:32 – the untagged VLAN will be your default VLAN however if I specify a number here

3:37 – like I like I'm going to the number you specify in this case 10 is the untagged

3:43 – vlan so I want to send traffic to VLAN 10 untag because that's going to

3:48 – our pc and our PC doesn't understand VLAN tagging and vlan 20 traffic will

3:52 – remain tagged and go to the phone

3:55 – so if I do a show interface e 1/1/1 it is going to tell me that it's a

4:03 – member of two layer 2 vlans the ports in dual mode in VLAN 10 so its

4:10 – port state is blocking because the ports down at the moment but its dual mode

4:13 – and VLAN 10 even though it's a member of to vlans

4:16 – alright so easy as that thanks for joining