The BOOTP and DHCP protocols are used for obtaining the IP address of the host along with the bootstrap information. The working of both protocols is different in some manner. DHCP protocol is the extended version of the BOOTP protocol.
The major difference between BOOTP and DHCP is that BOOTP support static configuration of the IP addresses while DHCP supports dynamic configuration. It means that DHCP automatically assigns and obtain the IP addresses from the computer connected to the internet and also have some additional features.
Content: BOOTP Vs DHCP
|Basis for comparison||BOOTP||DHCP|
|Autoconfiguration||Not possible only supports manual configuration.||It automatically obtains and assigns IP addresses.
|Temporary IP addressing||Not provided||Provided for a limited amount of time.
|Compatibility||Not compatible with DHCP clients.||Interoperable with the BOOTP clients.|
|Mobile machines||IP Configuration and information access are not possible.||Supports mobility of machines.|
|Error occurance||Mannual configuration is prone to errors.||Autoconfiguration is immune to errors.|
|Usage||Provides the information to the diskless computer or workstation.||It requires disks to store and forward the information.
Definition of BOOTP
Bootstrap Process – It is a process of accessing the information of an internet connected computer such as (IP address, subnet mask, router address, IP address of the name server) stored in a configuration file these pieces for information are must be known to the computer connected to a TCP/IP internet.
Bootstrap Protocol (BOOTP) is a client-server protocol designed to obtain the above given information (i.e., IP address, subnet mask, router address, IP address of the name server) from a diskless computer or a computer booted for the first time. If the computer or workstation is diskless the operating system and networking software are stored in the read-only memory (ROM).
RARP is the predecessor of BOOTP and serves the same purpose, but the limitation of the RARP is that it only provides the information about IP not the extra information regarding that.
As described above the BOOTP protocol is static configuration protocol.The reason behind the BOOTP static nature is that the need of dynamically discover routers or change router is eliminated when only one router is connected to the rest of the internet. However, if there are multiple routers are connected to the internet. A host attempts to obtain the default route at the startup can result in connection loss if a single router crashes. And also the crash can be not detected.
BOOTP server uses a table that has a mapping of the physical address to the IP address when a client requests its IP address. BOOTP does not support mobile machines; it works well only when the binding between Physical and IP addresses is static and fixed in the table. It uses limited broadcast address (255.255.255.255).
Definition of DHCP
Dynamic host configuration protocol (DHCP) assigns the IP addresses dynamically over the network. DHCP is more versatile than BOOTP, and it is backward compatible which means that it can interoperate with BOOTP clients.
Dynamic assignment of IP addresses is desirable for several three reasons-
- IP addresses are assigned on demand.
- Avoid manual IP configuration.
- Support mobility of devices.
IP assignment on demand means suppose there is a shortage of real IP addresses then IP addresses are pooled centrally. If one wants to use the internet, then the IP address is assigned on the temporary basis, when work is done the IP address is withdrawn and given to some other user (machine).
DHCP supports temporary allocation (leases) of IP addresses. In other words, the IP’s are assigned for a limited amount of time and as the lease expires the IP’s are withdrawn. DHCP is necessary for the wireless networks where these computers can attach and detach quickly.
DHCP uses three timers :
- Lease Renewal Timer – Client machine uses this for sending DHCP request to ask the server for more time as this timer expires.
- Lease Rebinding Timer – When this timer expires, no responses are received by the client, and it is assumed that server is down. Then by using IP broadcast service, the DHCP request is sent to all the servers.
- Lease Expiry Timer – When this timer expires, system start crashing because the host does not have a valid IP address in the network.
Key Differences Between BOOTP and DHCP
- BOOTP is a static protocol, and it supports manual configuration. On the other hand, DHCP is dynamic protocol, and it supports manual, dynamic and autoconfiguration of IP addresses.
- On-demand IP addressing is provided in DHCP whereas BOOTP does not support temporary allocation (leases) of IP addresses.
- DHCP can handle mobile machines. In contrast, BOOTP is not able to configure or access information from mobile machines; and it only works well with stationary connections.
- BOOTP is prone to errors because of using manual configuration while in DHCP error occur seldomly.
BOOTP and DHCP are the protocols which a host uses to access or configure IP parameters from the server. DHCP is the extension of BOOTP. In BOOTP these operations take place at the boot time of host. DHCP is popular with ISP’s because it allows a host to obtain a temporary IP address while this is not the case in BOOTP. DHCP provides more detailed information and is more efficient than BOOTP.