Group signals together using the alt/else, opt, loop, and par keywords.
Alice->Bob: Authentication Request
alt successful case
Bob->Alice: Authentication Accepted
else some kind of failure
Bob->Alice: Authentication Failure
opt
loop 1000 times
Alice->Bob: DNS Attack
end
end
else Another type of failure
Bob->Alice: Please repeat
end
Group signals together using the alt/else, opt, loop, and par keywords.