| 摘要 |
<p>To solve the problem with mobile phone carriers that increasing mail traffic increases storage capacity of a mail server and network load, a relay server (106) which relays a mail transfer (SMTP communication) and a mail fetch (IMAP communication) is installed in a carrier facility network (103). The relay server (106) compresses a mail (304) including a header transferred from a mail transfer server (105), adds a new header to encapsulate the mail, and transmits the encapsulated mail to an IMAP server (107) as a compressed mail (308). In response to a mail fetch request from a communication terminal (101), the relay server (106) decapsulates and restores the compressed mail (308) fetched from the IMAP server (107), and transmits the restored mail to the communication terminal (101). The relay server (106) changes parameters such as the mail size, so that no inconsistency of IMAP commands occurs in compressing/restoring the mail.</p> |
