Original scientific paperThe increasing number of portable computers, combined with the growth of wireless services, makes supporting Internet mobility important. Since a mobile node always changes its point of attachment to the Internet, it may cross a cell boundary during data transmission process. Packets sequence disruption during handover procedure may result in decreasing network performance especially in higher layers protocols. In this paper we investigate the behavior of Mobile IP protocol in presence of route optimization procedure. We discuss the impact of handover process on packets routed from old Foreign Agent to new Foreign Agent after handover and show that using priority scheduling for packets received from the Home Agent and queued at the old Foreign Agent's buffer after handover can reduce the number of disordered packets received at the new Foreign Agent after handover.Key words: MIPv4, MIPv6, TCP performance, Priority scheduling, HandoverUnaprijeivanje mobilnog IP-a rasporeivanjem zasnovanom na prioritetima. Sve veći i veći broj prijenosnih računala, kombinirano s razvijanjem bežičnih usluga,čine podršku mobilnom Internet od velike važnosti. Pošto mobilničvor ima promijenjivu točku spajanja, može se dogoditi da prijee granicućelije tijekom prijenosa podataka što može izazvati smanjenje kvalitete usluge, pogotovo kod viših slojeva protokola. U ovomečlanku analizira se ponašanje mobilnog IP-a uz optimizaciju postupka usmjeravanja. Razmatra se utjecaj na razmjenu podataka izmeu starog agenta i novog agenta te se pokazuje da rasporeivanje zasnovano na prioritetima smanjuje broj nerasporeenih paketa.Ključne riječi: MIPv4, MIPv6, TCP učinkovitost, rasporeivanje zasnovanom na prioritetima, razmjena podataka