Introduction
By immediately nosotros should experience comfortable alongside price such as 'VLAN', 'Static & Dynamic VLANs', but this is exactly the offset inwards this complex world. On this page, nosotros volition start to piece of cake expand on these price past times introducing novel ones!
To laid about with, nosotros volition receive got a closer await at the port interfaces on these smart switches too and thus start moving towards the interfaces connecting to the network backbone where things driblet dead slightly to a greater extent than complicated, though produce non hold out alarmed since our detailed too piece of cake to read diagrams are hither to ensure the learning procedure is as enjoyable as possible.
VLAN Links - Interfaces
When within the footing of VLANs at that spot are ii types of interfaces, or if you lot like, links. These links allow us to connect multiple switches together or exactly elementary network devices e.g PC, that volition access the VLAN network. Depending on their configuration, they are called Access Links, or Trunk Links.
Access Links
Access Links are the most mutual type of links on whatever VLAN switch. All network hosts connect to the switch's Access Links inwards club to gain access to the local network. These links are your ordinary ports flora on every switch, but configured inwards a especial way, thus you lot are able to plug a reckoner into them too access your network.
Here's a pic of a Cisco Catalyst 3550 serial switch, alongside it's Access Links (ports) marked inwards the Green circle:
We must banking firm notation that the 'Access Link' term describes a configured port - this agency that the ports higher upwards tin forcefulness out hold out configured as the minute type of VLAN links - Trunk Links. What nosotros are showing hither is what's commonly configured as an Access Link port inwards 95% of all switches. Depending on your needs, you lot mightiness require to configure the firstly port (top left corner) as a Trunk Link, inwards which case, it is plainly non called a Access Link port anymore, but a Trunk Link!
When configuring ports on a switch to human action as Access Links, nosotros commonly configure solely 1 VLAN per port, that is, the VLAN our device volition hold out allowed to access. If you lot recall the diagram below which was also nowadays during the introduction of the VLAN concept, you'll meet that each PC is assigned to a specific port:
In this case, each of the half-dozen ports used receive got been configured for a specific VLAN. Ports 1, 2 too iii receive got been assigned to VLAN 1 spell ports 4, v too half-dozen to VLAN 2.
In the higher upwards diagram, this translates to allowing solely VLAN 1 traffic inwards too out of ports 1, 2 too 3, spell ports 4, v too half-dozen volition bear VLAN 2 traffic. As you lot would remember, these ii VLANs produce non telephone substitution whatever traffic betwixt each other, unless nosotros are using a layer iii switch (or router) too nosotros receive got explicitly configured the switch to route traffic betwixt the ii VLANs.
It is as of import to banking firm notation at this betoken that whatever device connected to an Access Link (port) is totally unaware of the VLAN assigned to the port. The device but assumes it is business office of a unmarried broadcast domain, exactly as it happens alongside whatever normal switch. During information transfers, whatever VLAN information or information from other VLANs is removed thus the recipient has no information nearly them.
The next diagram illustrates this to help you lot acquire the picture:
As shown, all packets arriving, entering or exiting the port are measure Ethernet II type packets which are understood past times the network device connected to the port. There is nix especial nearly these packets, other than the fact that they belong solely to the VLAN the port is configured for.
If, for example, nosotros configured the port shown higher upwards for VLAN 1, too thus whatever packets entering/exiting this port would hold out for that VLAN only. In addition, if nosotros decided to utilization a logical network such as 192.168.0.0 alongside a default subnet mask of 255.255.255.0 (/24), too thus all network devices connecting to ports assigned to VLAN 1 must hold out configured alongside the appropriate network address thus they may communicate alongside all other hosts inwards the same VLAN.
Trunk Links
What we've seen thus far is a switch port configured to bear solely 1 VLAN, that is, an Access Link port. There is, however, 1 to a greater extent than type of port configuration which nosotros mentioned inwards the introductory department on this page - the Trunk Link.
Influenza A virus subtype H5N1 Trunk Link, or 'Trunk' is a port configured to bear packets for whatever VLAN. These type of ports are commonly flora inwards connections betwixt switches. These links require the powerfulness to bear packets from all available VLANs because VLANs bridge over multiple switches.
The diagram below shows multiple switches connected throughout a network too the Trunk Links are marked inwards majestic color to help you lot position them:
As you lot tin forcefulness out meet inwards our diagram, our switches connect to the network backbone via the Trunk Links. This allows all VLANs created inwards our network to propagate throughout the whole network. Now inwards the unlikely final result of Trunk Link failure on 1 of our switches, the devices connected to that switch's ports would hold out isolated from the balance of the network, allowing solely ports on that switch, belonging to the same VLAN, to communicate alongside each other.
So immediately that nosotros receive got an persuasion of what Trunk Links are too their purpose, let's receive got a await at an actual switch to position a possible Trunk Link:
As nosotros noted alongside the explanation of Access Link ports, the term 'Trunk Link' describes a configured port. In this case, the Gigabit ports are commonly configured as Trunk Links, connecting the switch to the network backbone at the speed of 1 Gigabit, spell the Access Link ports connect at 100Mbits.
In addition, nosotros should banking firm notation that for a port or link to operate as a Trunk Link, it is imperative that it runs at speeds of 100Mbit or greater. Influenza A virus subtype H5N1 port running at speeds of 10Mbit's cannot operate as a Trunk Link too this is logical because a Trunk Link is ever used to connect to the network backbone, which must operate at speeds greater than most Access Links!
Summary
This page introduced the Access too Trunk links. We volition hold out seeing a lot of both links from immediately on, thus it's best you lot acquire comfortable alongside them! Configuration of these links is covered afterwards on, because at that spot is soundless quite a combat of theory to cover!
