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ME60 V800R010C10SPC500 Feature Description - WAN Access 01

This is ME60 V800R010C10SPC500 Feature Description - WAN Access
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Comparison Between OSPFv3 and OSPFv2

Comparison Between OSPFv3 and OSPFv2

OSPFv3 and OSPFv2 are the same in the following aspects:

  • Network types and interface types

  • Interface state machines and neighbor state machines

  • LSDB

  • Flooding mechanism

  • Five types of packets: Hello, DD, LSR, LSU, and LSAck packets

  • Route calculation

OSPFv3 and OSPFv2 differ as follows:

  • In OSPFv3, only LSUs contain IP addresses.

  • OSPFv3 uses IPv6 which is based on links rather than network segments.

    Therefore, the interfaces on which OSPFv3 is to be configured must be on the same link rather than in the same network segment. In addition, the interfaces can establish OSPFv3 sessions without IPv6 global addresses.

  • OSPFv3 does not depend on IP addresses.

    OSPFv3 separates topology calculation from IP addresses. Specifically, OSPFv3 can calculate the OSPFv3 topology without IPv6 global addresses which only apply to virtual link interfaces and packet forwarding.

  • OSPFv3 packets and the LSA format change.

    • OSPFv3 packets do not contain IP addresses.

    • OSPFv3 router LSAs and network LSAs do not contain IP addresses, which are advertised through link LSAs and intra-area prefix LSAs.

    • In OSPFv3, router IDs, area IDs, and LSA link state IDs no longer indicate IP addresses, but the IPv4 address format is still reserved.

    • Neighbors are identified by router IDs instead of IP addresses on broadcast, NBMA, or P2MP networks.

  • Information about the flooding scope is added to OSPFv3 LSAs.

    Information about the flooding scope is added to the LSA Type field of OSPFv3 LSAs. Therefore, OSPFv3 routers can process LSAs of unidentified types more flexibly.

    • OSPFv3 can store or flood unidentified packets, whereas OSPFv2 discards unidentified packets.

    • In OSPFv3, unknown LSAs with 1 as the U flag bit can be flooded, and the flooding scope of such LSAs is specified by the LSAs.

    For example, Device A and Device B can identify LSAs of a certain type. Device A and Device B are connected through Device C which, however, cannot identify these LSAs. If Device A floods such LSA to Device C, Device C can still flood the received LSAs to Device B although Device C does not identify these LSAs. Device B then processes these LSAs.

    If OSPFv2 is run, Device C discards the unidentified LSAs. As a result, these LSAs cannot reach Device B.

  • OSPFv3 supports multi-process on a link.

    In OSPFv2, one physical interface can be bound to only one multi-instance. In OSPFv3, one physical interface can be bound to multiple multi-instances that are identified by different instance IDs. In these OSPFv3 multi-instances running on one physical interface, neighbor relationships are established separately, sharing resources on the same link.

  • OSPFv3 uses IPv6 link-local addresses.

    IPv6 implements neighbor discovery and automatic configuration based on link-local addresses. Routers running IPv6 do not forward IPv6 packets whose destination address is a link-local address, and those packets can only be exchanged on the same link. The unicast link-local address starts from FE80/10.

    As a routing protocol running on IPv6, OSPFv3 also uses link-local addresses to maintain neighbor relationships and update LSDBs. Except Vlink interfaces, all OSPFv3 interfaces use link-local addresses as the source address and the next hop to transmit OSPFv3 packets.

    The advantages are as follows:
    • OSPFv3 can calculate the topology without global IPv6 addresses.

    • The packets flooded on a link are not transmitted to other links, which prevents unnecessary flooding and saves bandwidth.

  • OSPFv3 supports two new LSAs.

    • Link LSA: A device floods a link LSA on the link where it resides to advertise its link-local address and the configured global IPv6 address.

    • Intra-area prefix LSA: A device advertises an intra-area prefix LSA in the local OSPF area to inform the other routers in the area or the network (either a broadcast network or an NBMA network) of its IPv6 global address.

  • OSPFv3 identifies neighbors based on Router IDs only.

    On broadcast, NBMA, and P2MP networks, OSPFv2 identifies neighbors based on IPv4 addresses of interfaces.

    OSPFv3 identifies neighbors based on Router IDs only.

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Updated: 2019-01-04

Document ID: EDOC1100059473

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