Satellite links do not use MAC addresses? Can some one please verify

[cnoel2050]

Hello evry one I am new to this community. I came across this while doing some studying this morning. Satellite links do not use MAC addresses. Point-to-point WAN links use their own layer 2 protocols and data link addressing scheme. MAC addresses are found only in Ethernet. Is this true or false? I welcome all feedback. Thanks, Claude

[davidmatthew0023 · Accepted solution]

It is not often that MAC addresses are used in satellite links, but other ways of addressing and routing are implemented. MAC addresses are used in a LAN environment, while for satellite communications, other protocols and technologies would be more applicable for long-distance and space-type communications.

[cnoel2050]

Thankyou @davidmatthew0023 for the feedback. This was very helpful.

[Giuseppe Larosa · Accepted solution]

Hello @cnoel2050 ,

it actually depends on the type of satellite communications implemented.

In some cases Ethernet frames are carried over satellite links giving a LAN like experience.

I worked more then 10 years ago  for a network integration for first satellite based broadband access for Eutelsat and in that case we had ethernet frames and IP involved. The satellite was dedicated to data communications

the RF physical link can use MAC addresses for contention on upstream traffic between different users. it is not a point to point  link but dynamically used.   ( similar case in cable modem networks  )

So contention control started with satellite communications then it was ported in the LAN.

see

https://www.geeksforgeeks.org/what-is-slotted-aloha/

No single user can pay for a satellite  . To give you an idea the satellite I have been referring to above had a cost or more then 400 millions of euros plus the cost to put it in the orbit.

Hope to help

Giuseppe

[cnoel2050]

@Giuseppe Larosa this was helpful and interesting to learn.I appreciate the feed back.

[Joseph W. Doherty]

What L2 addressing boils down, can there be more than two nodes?  If not, such as on any p2p link, you don't need any L2 addressing, and if you don't, it's just wasted bandwidth.

Interestingly, even on IP, for p2p, we can reduce IP address allocation using unnumbered interfaces or /31s.  Both work because there's only 2 nodes.

Usually, the size of a L2 address is designed to handle what's considered a reasonable number of nodes.  What's a bit strange about Ethernet MACs, they were sized to allow, in theory, a globally unique address.  I don't know why that was done, perhaps to simplify deployment(?).