[...]... internal and/or leaf databases Large CMR Call Stability Forwarding Pointers When x moves from cell i to cell j, instead of updating all databases on the path from i to LCA(i, j) and from LCA(i, j) to j, update all databases up to some level m and add a forwarding pointer at the level m ancestor of i to point to the level m ancestor of j When and how to purge the forwarding pointers Small LCMR Setting... Per object, group of objects, geographical region Variations Dynamic (adaptive) or static Variations Method Eager caching: When x is called by y, cache x’s location at y’s zone Call Stability Lazy caching: Forwarding Pointers When x moves, add a forwarding pointer from its old to its new address Cache update overhead occurs at calls Per-user Profile Replication: Additional constraints are set on the... !ŸÝ1‘o&ˆ¬ƠŸƯŸß©™vibƒß™lỵ™~I#¡ Issues/Variations Method Caching When x at zone i is called by user y at zone j, cache at a node on the path from j to LCA(i, j) a pointer to a node on the path from i to LCA(i, j) to be used by any subsequent call to x from zone j Up to which tree level to maintain cache entries Ĩ ÜƠ Ị Þ × Õ ỴáƠ !1¨™S݈rr™11× Caching Applicable when: Cache update overhead occurs at moves... number of replicas per site and on the number of replicas per user Working Set: Adaptive and distributed: the replication sites are computed dynamically by each mobile host locally Replication Selectively replicate x’s address at the zones from which it receives the most calls Large LCMR Restrict the length of the chain of forwarding pointers Large LCMR Call Stability Small LCMR  © ¢  Ĩ Ĩ Ïø Ư Ýé á ¤... When and how to purge the forwarding pointers Small LCMR Setting the level m Partitions Divide the locations into sets (partitions) so that the user moves inside a partition frequently and crosses the boundary of a partition rarely Keep information about the partition in which the user resides instead of its exact location Move Stability ä×Ĩ ÚĨ ÜÏ ø Ỵ ƯƠáÏ Ý ßá Ư ÜÏỊáỊ Ư 6 ÝƠ ×Ơ ỴĨ ÚĨÏ Ỵá Ü Ỵ ÕĨ× Ý âÝỊ... g¡™—‘1‘—#¡™~¬Ĩm~¨vŸÝil|~EŸỴ€b1‘o¡ŸĨ|•¡Ĩ’¬Ĩ©¤™I¦ |~EŸỴ€"’!ŸỴ—|‘¨|™!´" 1!€Ÿà"ë ¥ user x old location 10 13 11 12 4 14 15 old entries for x new entries for x user x new location 16 5 17 18 19 6 20 21 22 23 24 26 27 3 2 Forwarding Pointer s 25 9 8 7 1 level m t 0 ò ™¥ ĨỊ á đ đ ÝƠ à Ư Õ á ß ×Ĩ× á Ø áƠ á Õ ßĨ ê ßãỊĨ Ü Ư Ü Ư × ƯỊƠ ỴĨ Ĩ ÜƠ Û ỴĨ Ü ¢ ä ÕĨƠ ßĨ Õ Ý ß á Ư đ đ Ơ á Ị Þ ÙỊƠ Ỵ 1‘6™’u!ŸỴ—™¡¬Ĩ¦¡™—‘1‘—G¡™~ŸĨŽ~!€¬àreŸỴ¦¡ŸĨ|•¡)r1™‰¡!6#‰¡~¬Ĩ¡!¤ƒ×™¦Ÿ×)™6‘i... ÜÏỊáỊ Ư Ư à Ư ÜÏá ÷ ò ĨỊ Đ Ư E¡¤€!¡ŸĨov!I1™’r1w™ˆ¬Ơ~ŸÏŸƯ©¤ŸÚ1™!¤~¡¤¡!gIø €¬Ý1‘~I#¦™~ƒÏr||‘g~¬Ĩm6 ŸỴtrŸỴr|™)y& i1!€¬à˜ë search procedure user x 10 11 12 13 14 4 s 5 15 6 16 reverse bypass pointer t 17 18 forward bypass pointer 1 19 20 22 21 23 24 25 26 27 9 8 7 3 2 0 đ Ỵ ƯƠá ß âĨỊ Ĩ ÜƠ Ư ß Ỵ Ý Û Ĩ Ỵ Ý á Ơá ÕĨƠá ß âĨỊ Ĩ Ø ß Đ Ý Ü× ỊĨ× Đ á ÞÝ Ỵ ƯƠáÏ ß Ĩ ÜƠ ßáỊĨ ỴĨà Ỵ €¬Ý1‘~ŸÏŸƯ©~1)!1r¬Þy¬Ùr€€r0 !€~! ¦‘¡‘~ƒÏŸƯ—~1¨bkŸÕ—€!1#$... ¡ 9 G ¥ ú×Ĩ××ĨỊ Õ Õá á èĨ ĨỊá × ƯỊƠ Ỵ ù ß â Úá è ×ỊĨƠ Ư Ý ư à Ư ÕỊá éỊÝ ë ĨỊ Đ Ư g¡1¡1rr™mc™!c¤1‘o¡ŸĨ|•¡Ĩ’¬Ĩ©¤™I¦ |~EŸỴ€"’!ŸỴ—|‘¨|™!´& 6 1!€Ÿà"ë ¥ user x old location user x new location Forwarding Pointer x | 14 10 11 12 4 13 x | 14 x | 17 14 15 16 old entries for x new entries for x x | 17 6 5 x | 17 17 18 19 1 20 21 22 23 24 x | 17 2 25 26 27 9 8 7 x | 14 3 level m x | 14 x | 14 0 (this entry... äú ƯƠá gE¬Ý1‘|Ị ï ÷ Õ ỴáÛÙ Ư ØáƠ øÛÙ ßáÏ Ý ÞÝ × Ỵ Ư× ỴĨ Ư 8 Ĩ ÜƠ à Ỵ ßá ×Ĩ Đ Ư Ỵ ÜÏĨ & ơđ ĨỊ Đ Ư )yr™q™ˆ¬ƠŸƯŸß©‘1G™™ˆ¬ƠŸƯ™~I#¡ ™br€¬Ý1—¡¤ŸÚA¨!1)!€ŸÝ™#¡!G rrg¡®¢ ~61!€¬à˜ë Partial updates - forward pointers Small LCMR Cache (replicate) Large LCMR Relative Frequence of Moves and Calls (LCMR) Cache (replicate) at frequent callers Partition the locations Calls Hierarchical structures Moves Stability Locality... !1ˆrŸỴ™1EŸỴ™’)E¡™‘©€¬Ý1c¡|¬Ịr¡1y©¡ŸĨŸß™~©€ŸÝ€~1—™~I¬ÝA!1#™A™¬ê1‘1E¡¡1r~|m!o¢ ~¡™v’›¡Ơ™Ý ¨ × Ỵ Ư ƯƠỊá ư & ĨỊ Đ Ư r€¬Ý1ŸƠ11‘˜´%¡ 1!€¬à˜ë Parttion 1 10 11 12 13 4 user x 14 15 Partition 2 user x new location 16 5 IN 1 17 Partition 4 Partition 3 18 19 20 7 P2 6 P1 22 21 23 24 25 26 27 9 8 P3 3 2 P4 0 ò ¡đ Ơá ÜƠ Ĩàá××Ĩ Ú Ơ ỴĨ Ú à Õ ß éÝ Ỵ íÏá Ỵá ỊĨ Ư× Ỵ ÝÏ Ý ßá Ĩ @ ä ÝƠ × ÕỊá é Ỵ éÝ Õ ỴĨ ÜƠ Õ Ỵá ú ¦ ù ¤ ¢   ÝƠ ‘r1)™‘|1¡¤´E¡¤€!¡¬Ĩmv!I1™’™¦~!ƒÕ1r€cŸ×™6†r0