1. A method of distributing information relating to a set of networks from a first node to a second node of a communication system, wherein a set of identifiers of respective networks which belong to the set of networks is stored at the first node, the method comprising: generating, at the first node, hash values for the identifiers in the set of identifiers using a hash function, wherein one of the identifiers in the set of identifiers is a partial identifier; transmitting the generated hash values from the first node to the second node; said transmitting causing the second node to determine an identifier of a particular network which is available for communicating with the second node; causing generation of, at the second node, a hash value for the identifier of the particular network using said hash function; and causing comparison of, at the second node, the hash value of the identifier of the particular network generated at the second node with the hash values received at the second node from the first node to thereby determine whether the particular network belongs to said set of networks, and wherein if the hash value of the identifier of the particular network does not match with any of the hash values received at the second node from the first node then the method comprises causing removal of a character from the identifier of the particular network and then repeating (i) causing generation of, at the second node, a hash value for the identifier of the particular network using said hash function and (ii) causing comparison of the hash value of the identifier of the particular network generated at the second node with the hash values received at the second node from the first node to thereby cause determination of whether the particular network belongs to said set of networks.