IPv4

[M.Sultan]

I experienced the multicast IPv4 address which is used in Dynamic routing protocols.

where the broadcast is used ?

NID 192.168.1.0 > this is used to advertise network in router, when the BID 192.168.1.255 is used with which protocol and where ?

Each network Ip has it's own broadcast ip address as well,

[Flavio Miranda]

Routing protocol use multicast not broadcast and when  they use broadcast, they will use 255.255.255.255

The network broadcast, like you mentioned ,has no function really. At lest not as I have knowledge. Basically is a conceptual address used to stablish the end of the host range and the begenning of a new network

[M.Sultan]

I stated the same, just tell me where in reall in use BID ?

[M02@rt37]

Hello @M.Sultan,

In regards to the network ID (NID) and broadcast ID (BID) you mentioned, the NID is used to identify a specific network while the BID is used to send a broadcast message to all devices on that network. The BID for the network 192.168.1.0/24 would be 192.168.1.255.

The use of the BID depends on the protocol being used. For example, in the Address Resolution Protocol (ARP), the BID is used to send an ARP request to all hosts on a network segment in order to find the MAC address of a specific IP address. Similarly, in the Internet Control Message Protocol (ICMP), the BID is used to send an ICMP echo request to all hosts on a network segment.

[M.Sultan]

Well, So when have NID 192.168.1.0 the BID 192.168.1.0 should be used as
BID for ARP destionatkon, Why ARP packet use general BID from
255.255.255.255 ???

RIPv1 use 255.255.255.255 as BID it is defined already i understand, But
When BID of each subnet is used ?

Example of per subnet BID :

10.255.255.255
192.168.1.255
172.31.255.255
and etc...

Each subnet has its own NID BID.

[M02@rt37]

@M.Sultan,

I think there may be some confusion regarding the use of the broadcast address in ARP. In ARP, the destination MAC address is obtained by broadcasting an ARP request message to all hosts on the same network using the broadcast address (which is typically the network's broadcast address, not the NID or BID). When a host with the requested IP address receives the ARP request, it replies with its own MAC address, which allows the sender of the ARP request to communicate with that host.

So in the case of the network with NID 192.168.1.0 and BID 192.168.1.255, the broadcast address (192.168.1.255) would be used for ARP requests on that network. The general broadcast address (255.255.255.255) is used in situations where the sender doesn't know the destination network or doesn't have a specific broadcast address to use.

As for the use of broadcast addresses in routing protocols, it depends on the specific protocol and its implementation. In some cases, the broadcast address may be used as the destination for protocol messages that need to be sent to all hosts on a network, such as RIP. However, other protocols may use a different destination address for broadcast messages, such as multicast addresses.

Regarding your question about per-subnet broadcast addresses, each subnet should have its own unique broadcast address, which is derived from the subnet's network ID by setting all host bits to 1. The examples you provided (10.255.255.255, 192.168.1.255, 172.31.255.255) are all valid broadcast addresses for specific subnets, but they may not be the only possible broadcast addresses for those subnets depending on the subnet mask used.

[Joseph W. Doherty]

BTW, I believe ARP request uses a L2 broadcast destination address and just a L2 frame, i.e. L3 broadcast IP, global or network, isn't used.

[M02@rt37]

@Joseph W. Doherty,

ARP requests are sent as L2 broadcast frames using the MAC address FF:FF:FF:FF:FF:FF as the destination. The request is broadcasted to all devices on the same broadcast domain, and the device that matches the requested IP address sends a unicast ARP reply back to the requesting device. L3 broadcast addresses are not used in ARP requests. Thank you for pointing that out.

[Joseph W. Doherty]

Off-the-top-of-my-head, don't recall any standard protocol that uses a network broadcast.

It can be used to broadcast to any specific network, it can be routed.

If you're wondering why the need for also having 1st IP in an address block reserved for a network prefix in addition to reserving last IP in an address block, you can search for that on the Internet.  Personally. I'm not totally convinced that two IPs, per address block truly were needed to be reserved (consider /31s and /32s).

[MHM Cisco World]

until Now I dont see any using of BID of any network except the case of 
DHCP relay and you need to forward the broadcast (L2) to Farm of Server.
that it. 
for routing always remember that the routing protocol use specific multicast IP and unicast IP it never use broadcast IP.

[M.Sultan]

RIPv1 did send update to all neighbours using 255.255.255.255 and then replaced with RIPv2 with some other features added.

After all full adjacency, RIPv1 did send routings based on source and destination but updates always send to all RIP routers and none RIP routers.