Hi,
End-to-End VLAN:
----------------
One of the unique properties of VLANs is that they can span multiple switches. The physical boundaries of where people and resources are located are removed. In Figure End-to-End a switched network has three VLANs spread across three switches: Accounting, Information Services, and Marketing.
Figure End-to-End A physical view of computers and a logical representation of VLANs. Note that all the servers are located off of one switch. In traditional networks, resources such as local file servers would usually be located in the same place as the users. Spreading the resources like this makes their management much harder and security harder still. Using VLANs, an administrator can create the illusion that the file server is on the same segment as the users that access it, even though the file server could be on a completely different floor in a completely different building. Figure End-to-End gives a detailed view of both a physical and logical representation of this concept.
End-to-end VLANs have the following characteristics:
----------------
1.Users are grouped into a VLAN based on function, not location.
2.The user belongs to the same VLAN no matter where she plugs her PC into the network (this requires Cisco's VMPS, which is discussed later in this chapter).
3.End-to-end VLANs are typically used for security reasons or for application or resource requirements.
4.End-to-end VLANs are difficult to implement and troubleshoot.
Local VLAN:
----------
The problem with end-to-end VLANs is that they become extremely difficult to maintain as the campus network grows and changes. Because of this, most network administrators of campus environments use local VLANs.
Unlike end-to-end VLANs, local VLANs are very easy to plan and implement. Local VLANs are based on geographic locations by demarcation at a hierarchical boundary (core, distribution, access). Therefore, a local VLAN would never span from an access layer to a core block. Because VLANs are created based on geographic or physical boundaries, it's not uncommon to see much of the traffic leaving the broadcast domain to access a resource. There are two generic rules when dealing with traffic flow: 80/20 and 20/80. The 80/20 rule assumes that 80% of the traffic stays local to a VLAN and 20% leaves a VLAN through a Layer 3 device. Local VLANs assume this premise. Note that with this implementation, VLANs are solely used to solve broadcast problems. With the 20/80 rule, 20% of the traffic stays within the VLAN and 80% leaves it. In this situation, a burden is placed on the Layer 3 device that is used to interconnect VLANs. Although they do introduce a latency issue because of the access of resources outside of the VLAN.
Please find the attachment for more details.
Thanks
Goutam
Pls rate if it works.
