ite, i.e. with the PDP context activated. Activation of PDP contexts are of two types: primary and secondary. When the UE opens the PDP context to any access point, it is called the primary context while any subsequent context to the same access point but with a different traffic class is called the secondary context. However, both contexts share the same IP address. The process of PDP context activation is as follows. Once the UE initiates the request for the PDP context activation, the request is received by the 3G SGSN. The request may include configuration options such as the access point name and/or the QoS profile, etc. The subscriber records are checked using the HLR by the SGSN. Once approved, the SGSN performs a DNS query which is responded to by one or more IP addresses. The IP address with the lowest cost routing is used. The radio access bearer (RAB) assignment is then completed by the RNC by establishing the RAB access using the UE. The SGSN then sends a PDP activation request to the GGSN. This request can be rejected or the QoS profile may be re-negotiated. Thus, after checking resources, the PDP context activation request is accepted. Mobile Packet Core Architecture Planning 4.13.1 VLAN Virtual LAN is a group of workstations and network devices that are grouped together to communicate irrespective of the physical locations. This concept uses switches to create isolated domains. The main advantage of VLAN is that it reduces unnecessary congestion in the network; e.g. in an LAN, when the host broadcasts a message, all the computers receive the message, which creates congestion in the network. Thus, when using the concept of VLAN, logical segmentation is done in the network, which reduces congestion as the traffic is reduced significantly in the network (the broadcast domain is confined), increases the ability to manage the network and, increases security (as traffic is separated). The grouping can be done by using MAC addresses, protocol type, IP addressing, application type, etc. The VLANs are propo