Ethernet format to send data to hose on different network

[andy1]

If my computer needs to send data to another host on a network halfway around the world, without knowing the MAC address, what would the frame format be?

For example, within an ethernet network, to send data to another hose in the same network, the sender would include the MAC address and the IP address of the receiver host. But if the receiver host is located halfway around the world in another network, then how would the sender know the MAC address?

The ethernet format specifies that a ethernet frame should contains the source MAC and IP address, destination MAC and IP address. I have three out of four. I still don't know the destination MAC address.

What would be the process here?

 

[dainis]

Re: Ethernet format to send data to hose on different networ

For sending packets on IP networks, is using gateway, that recives all packets, that destination is not in local Ethernet network (defined by netmask).
Gateway MAC address is getting by ARP protocol. Gateway send IP packet to other
gateway or destination Ethernet net, if it connected directly to one gateway ethernet interface.

 

[andy1]

Re: Ethernet format to send data to hose on different networ

Upon receiving the IP package, how does the gateway find out if it should forward the message to other gateway?

In other words, what in the message frame that determine that the message is not meant for the gateway, but the message is to be forwarded to other gateways?

 

[dainis]

Re: Ethernet format to send data to hose on different networ

Upon receiving the IP package, how does the gateway find out if it should forward the message to other gateway?

In other words, what in the message frame that determine that the message is not meant for the gateway, but the message is to be forwarded to other gateways?

Yes, more detailed:
If IP packet destination (IP) address is not for this gateway (router) or directly connected network this router send IP packet to other router, by routing table rules, that can be set manually (static routes) or by routing protocol (RIP, OSPF, BGP ....), or default gateway (it is more used for small home or SOHO internet connections).

 

[lambtron]

Re: Ethernet format to send data to hose on different networ

Upon receiving the IP package, how does the gateway find out if it should forward the message to other gateway?

In other words, what in the message frame that determine that the message is not meant for the gateway, but the message is to be forwarded to other gateways?

The decision depends on whether the IP address is "private." The following IP address ranges are reserved for private networks:

10.x.x.x
192.168.x.x
172.16.x.x to 172.31.x.x

All other address ranges may be (but are not required to be) public addresses and so are not recommended for private LANs.

For example, 192.173.4.5 may be a public address, whereas 192.168.4.5 is guaranteed to be a private address.

The router will send a packet out onto the wan only if its destination IP address is not private.