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Configuration Guide - IP Unicast Routing

CloudEngine 12800 and 12800E V200R002C50

This document describes the configurations of IP Unicast Routing, including IP Routing, Static Route, RIP, RIPng, OSPF, OSPFv3, IPv4 IS-IS, IPv6 IS-IS, BGP, Routing Policy, and PBR.

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Configuring the ECMP Load Balancing Mode

Configuring the ECMP Load Balancing Mode

Context

Equal-Cost Multi-Path routing (ECMP) implements load balancing and link backup. ECMP applies to the network where multiple links to the same destination are available. In the traditional routing technology, packets are forwarded to the destination through one link only; the other links are in backup or inactive state; switching between these links requires a certain period when dynamic routes are used. Different from the traditional routing technology, ECMP can use multiple links to increase transmission bandwidth and transmit data on a faulty link without any delay or packet loss. ECMP is classified into per-flow load balancing and per-packet load balancing. Per-flow load balancing can ensure the packet sequence and ensure that the same data flow is forwarded using the same route and different data flows are forwarded using different routes. Per-packet load balancing can improve ECMP bandwidth efficiency to ensure even load balancing among equal-cost routes, but cannot prevent packet mis-sequencing. To ensure packet sequencing, confirm that the device or terminal that receives traffic supports packet reassembly in case of packet mis-sequencing.

NOTE:

In ECMP, CE12800s will calculate the hash value according to the first 128 bytes or the two headers ranges starting with the forwarding byte of packets for load balancing.

Per-packet load balancing takes precedence over per-flow load balancing. When both of them are configured, per-packet load balancing takes effect.

In per-packet load balancing, devices support the following load balancing modes:
  • random mode: A route is randomly selected among multiple equal-cost routes to forward packets. When the IP address and MAC address of known unicast packets remain unchanged, configure random per-packet load balancing.
  • round-robin mode: Each equal-cost route, in turn, is used to forward packets. When known unicast packets have the similar length, configure round-robin per-packet load balancing.

The CE12800 series switches support only round-robin per-packet load balancing.

In per-flow load balancing, devices support different load balancing modes for different packets, as listed in Table 1-5, Table 1-6.

Table 1-5 Load balancing modes for different packets (only on the CE6870EI) (CE12800)

Packets (on the Inbound Interface)

Default Load Balancing Mode

Configurable Load Balancing Mode

IPv4 packets src-ip, dst-ip, l4-src-port, and l4-dst-port

src-ip, dst-ip, l4-src-port, l4-dst-port, and protocol

IPv6 packets src-ip, dst-ip, l4-src-port, and l4-dst-port

src-ip, dst-ip, and protocol

NOTE:

IPv6 packet load balancing modes, l4-src-port and l4-dst-port are controlled by the l4-src-port and l4-dst-port fields of IPv4 packets. That is, when the load balancing modes of IPv4 packets include l4-src-port or l4-dst-port, the l4-src-port or l4-dst-port field also participates in load balancing of IPv6 packets.

TRILL packets Ingress: Non-IP packets are load balanced based on the inner src-mac, vlan, and dst-mac. IP packets are load balanced based on src-ip, dst-ip, l4-src-port, and l4-dst-port.

src-ip, dst-ip, l4-src-port, l4-dst-port, protocol, vlan, and src-interface

Transit/Egress: Packets are load balanced based on the inner src-mac and dst-mac.

The load balancing mode cannot be configured.

MPLS packets

Ingress/Egress: top-label, 2nd-label, and fields in the inner IP header (src-ip, dst-ip, l4-src-port, and l4-dst-port or ipv6 src-ip, and ipv6 dst-ip)

Transit: top-label, 2nd-label, and fields in the inner IP header (src-ip, and dst-ip or ipv6 src-ip, and ipv6 dst-ip)

top-label, 2nd-label, 3rd-label
NOTE:
  • If EA/EC/ED/EF/EG/BA/CE-FWA/CE-IPSA series cards are used:
    • On an egress node, the load balancing mode based on fields in the inner IP header (src-ip, dst-ip, l4-src-port, and l4-dst-port or ipv6 src-ip and ipv6 dst-ip) does not need to be configured, but the fields that participate in load balancing are affected by the load balancing mode configuration of IPv4 packets and IPv6 packets. If the l4-src-port and l4-dst-port fields are specified in the configured load balancing mode, packets may be unable to be load balanced in the configured load balancing mode. To prevent this problem, cancel the configuration of the l4-src-port and l4-dst-port fields in the load balancing mode of IPv4 packets.
    • On a transit node, the load balancing mode based on fields in the inner IP header (src-ip and dst-ip or ipv6 src-ip and ipv6 dst-ip) does not need to be configured. However, the fields that participate in load balancing are affected by the load balancing mode configuration of IPv4 packets and IPv6 packets, and the l4-src-port and l4-dst-port fields do not participate in the load balancing of MPLS packets.
  • If FD/FDA series cards are used:
    • On an egress node, the load balancing mode based on fields in the inner IP header (src-ip, dst-ip, l4-src-port, and l4-dst-port or ipv6 src-ip and ipv6 dst-ip) does not need to be configured, but the fields that participate in load balancing are affected by the load balancing mode configuration of IPv4 packets and IPv6 packets. If the l4-src-port and l4-dst-port fields are specified in the configured load balancing mode, packets may be unable to be load balanced in the configured load balancing mode. To prevent this problem, cancel the configuration of the l4-src-port and l4-dst-port fields in the load balancing mode of IPv4 packets.
    • On a transit node, the load balancing mode based on fields in the inner IP header (src-ip and dst-ip or ipv6 src-ip and ipv6 dst-ip) does not need to be configured, but the fields that participate in load balancing are affected by the load balancing mode configuration of IPv4 packets and IPv6 packets.

VPLS packets

Transit:
  • For FD/FDA series cards: top-label, 2nd-label, and fields in the inner Ethernet header (src-mac and dst-mac)
  • For other cards: top-label, 2nd-label
inner-sip and inner-dip
NOTE:
  • The load balancing mode based on fields in the inner Ethernet header (src-mac and dst-mac) does not need to be configured, but the fields that participate in load balancing are affected by the load balancing mode configuration of the l2 [ src-mac | dst-mac | vlan | eth-type ] * command.
  • The load balancing mode based on top-label and 2nd-label is affected by the load balancing mode configuration of MPLS packets. In an inter-AS VPLS Option C scenario, after PHP is disabled, if packets carry three labels, packets can be load balanced only based on the top-label and 2nd-label fields of MPLS packets. If packets carry more than three labels, packets can be load balanced only based on the outer label.

VXLAN packets

l4-src-port

inner-src-mac, inner-dst-mac, inner-src-ip, inner-dst-ip, inner-l4-src-port, inner-l4-dst-port, inner-protocol, and l4-src-port

Table 1-6 Load balancing modes for different packets (only on the CE12800E)

Packets (on the Inbound Interface)

Default Load Balancing Mode

Configurable Load Balancing Mode

IP packets src-ip, dst-ip, l4-src-port, l4-dst-port

src-ip, dst-ip, l4-src-port, l4-dst-port, protocol, vlan, src-interface, dscp

GRE packets, 6over4 packets Non-IP packets are load balanced based on the inner inner-src-ip, inner-dst-ip, inner-l4-dport, inner-l4-sport. IP packets are load balanced based on src-ip, dst-ip, l4-src-port, and l4-dst-port. inner-src-ip, inner-dst-ip, inner-l4-dport, inner-l4-sport

Procedure

  • Configure ECMP load balancing (only on the CE6870EI) (For the CE12800).
    1. Run system-view

      The system view is displayed.

    2. Run load-balance profile profile-name

      An enhanced load balancing profile is created, and the load balancing profile view is displayed.

    3. You can perform one, multiple, or none of the following operations.

      • Run ip [ dst-ip | l4-dst-port | l4-src-port | protocol | src-ip ] *

        The load balancing mode of IPv4 packets is set in the load balancing profile.

      • Run ipv6 [ dst-ip | protocol | src-ip ] *

        The load balancing mode of IPv6 packets is set in the enhanced load balancing profile.

        NOTE:

        IPv6 packet load balancing modes, l4-src-port and l4-dst-port are controlled by the l4-src-port and l4-dst-port fields of IPv4 packets. That is, when the load balancing modes of IPv4 packets include l4-src-port or l4-dst-port, the l4-src-port or l4-dst-port field also participates in load balancing of IPv6 packets.

      • Run mpls [ 2nd-label | 3rd-label | top-label ] *

        The load balancing mode of MPLS packets is set in the load balancing profile.

        By default, load balancing of MPLS packets is based on the two outer labels (top-label and 2nd-label) of each packet.

      • Run vxlan { inner-src-mac | inner-dst-mac | inner-src-ip | inner-dst-ip | inner-l4-src-port | inner-l4-dst-port | inner-protocol | l4-src-port | shift shift-data } *

        A load balancing mode of VXLAN packets in a load balancing file is specified.

        By default, VXLAN packets load balancing is based on l4-src-port.

        The command is not supported by the cards in CE-L48GT-EA, CE-L48GT-EC, CE-L48GS-EA, CE-L48GS-EC, CE-L24XS-BA, CE-L24XS-EA, CE-L48XS-BA, CE-L48XS-EA and CE-L24LQ-EA. Do not use these cards with cards supporting this command; otherwise, load balancing is uneven.

    4. Run ecmp { src-interface | seed seed-data } *

      The ECMP load balancing mode is set in the enhanced load balancing profile.

      By default, the ECMP load balancing mode is seed.

    5. Run ecmp universal-id universal-id

      The hash algorithm offset of ECMP load balancing is set in the enhanced load balancing profile.

      By default, the hash algorithm offset of ECMP is 1.

      NOTE:

      The default universal-id in ECMP load balancing is 11 in V100R005C00 and 1 in other versions. After an upgrade to V100R005C00, the default universal-id is changed from 1 to 11. After an upgrade from V100R005C00 to another version, the default universal-id is changed from 11 to 1. In V100R005C10 and later versions, you can run the ecmp universal-id universal-id command to change the universal-id and adjust the forwarding path calculated using the hash algorithm.

    6. Run ecmp hash-mode hashmode-id

      The hash algorithm mode used in ECMP load balancing is configured.

      By default, the hash algorithm mode used in ECMP load balancing is 2. Set the hash algorithm mode to 3/4/5 for per-packet load balancing.

    7. Run ecmp local-preference enable

      Local traffic preferential forwarding is enabled.

      By default, local traffic preferential forwarding is disabled.

    8. Run commit

      The configuration is committed.

  • Configure the ECMP load balancing mode (on the CE12800E).
    1. Run system-view

      The system view is displayed.

    2. Run load-balance ecmp

      The ECMP view is displayed.

    3. Perform the following operations according to network packet types.

      • Run ip { src-ip | dst-ip | vlan | l4-src-port | l4-dst-port | protocol | src-interface | dscp } *

        A load balancing mode is configured for IP packets in ECMP.

      • Run ip-tunnel { inner-src-ip | inner-dst-ip | inner-l4-sport | inner-l4-dport } *

        A load balancing mode is configured for GRE packets and 6over4 packets in ECMP.

    4. Run hashmode hashmode-id

      The hash algorithm mode used in ECMP load balancing is configured.

      By default, the hash algorithm mode used in ECMP load balancing is 0. Set the hash algorithm mode to 1 for per-packet load balancing.

    5. Run local-preference enable

      Local traffic preferential forwarding is enabled.

      By default, local traffic preferential forwarding is disabled.

    6. Run commit

      The configuration is committed.

  • Configure simulated calculation of an ECMP outbound interface.

    Run display load-balance forwarding-path unicast interface ecmp { vlan vlan-id | src-interface interface-type interface-number | vpn-instance vpn-instance-name | src-ip src-ip-data | dst-ip dst-ip-data | protocol { protocol-number | icmp | igmp | ip | ospf | tcp [ l4-src-port src-port-data | l4-dst-port dst-port-data ] * | udp [ l4-src-port src-port-data | l4-dst-port dst-port-data ] * } } * slot slot-id

    Simulated calculation of an ECMP outbound interface is configured after the 5-tuple information, source MAC address, and destination address are specified.

    NOTE:

    You cannot configure simulated calculation of an ECMP outbound interface on the CE12800E.

Verifying the Configuration

Run the display port forwarding-path { src-ip src-ip-data [ ip-mask-len | source-ip-mask ] | dst-ip dst-ip-data [ ip-mask-len | dst-ip-mask ] | src-mac src-mac-data | dst-mac dst-mac-data | protocol { protocol-number | gre | icmp | igmp | ip | ipinip | ospf | tcp [ l4-src-port src-port-data | l4-dst-port dst-port-data ]* | udp [ l4-src-port src-port-data | l4-dst-port dst-port-data ] * } } * [ enhanced ] command to check the outbound interface of packets that contain specified 5-tuple information, source MAC address, and destination MAC address.

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Updated: 2019-03-21

Document ID: EDOC1000166601

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