A router is a layer three device, which works on IP addresses. It has become an essential part of a network due to the shifting from wired connections to wireless.
Wireless connections bring more security risks to the network, though the advanced protocols of routers become quite difficult to break at the same time.
Difference between virtual routers and physical routers
Virtual routers are the same as physical routers and used as an access point for the communication between client and other networks or the internet. But the main difference between a virtual and physical router is the state of the router.
Virtual routers are usually in a static form without any interaction with the clients or other networks. It becomes active only when the first router, or master router, go down or unable to provide services. That is why virtual routers are also called backup routers.
The shifting of rights, services, from the master router to the backup router is performed directly without any interruption in services. The protocol responsible for the smooth transfer of services from one router to another is known as VRRP (virtual router redundancy protocol). The protocol is defined in RFC 2338 and RFC 5798.
A virtual router has its own VRID (Virtual Router Identifier) and attached MAC address and IP address, same as the normal physical router.
Some of the important fields of VRRP packets include priority field and authentication type field. The priority depends on the value of the priority field, which has values from 0 to 255, and the master has the priority field value 255 while virtual has 0. Virtual router operators in three basic modes which include backup state, master state, and initialise state.
A physical router is a general router use for communication between client and other networks or the internet. It is also called logic router due to its routing of IP packets based on the addresses present in the routing table of routers. In case of using a physical router as a backup, not using VRRP, the transfer of services from master to backup will not be arranged directly, unless the routing table of the backup router is filled manually.
Physical routers also have MAC address and IP address. They do not include any priority level field in its packets.
In the below example consider R1 as the master router providing services to CLIENT PC, while R2 is the virtual or backup router. In case the R1 goes down in the middle of when CLIENT PC was searching for something on the internet. So in that case, CLIENT PC will be directly connected to R2, virtual router, without any interruption in the services.
Consider the same example and scenario for two physical routers. In case R1 goes down, internet services for CLIENT PC will be down until the entries of the routing table of R2 are filled manually.