Appendix: Default Hash Factors

ECMP (Route & Tunnel) Load Balance

Table 1 Default Hash Factors in ECMP Load Balance Scenario

Scenarios

Traffic Type

Default Hash Factors

IPv4 unicast forwarding (including IPv4 L3VPN forwarding on Ingress PE(AC->MPLS or AC->AC))

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

IPv6 unicast forwarding (including IPv6 L3VPN forwarding on Ingress PE(AC->MPLS or AC->AC))

TCP/UDP

5-tuple <source IPv6, destination IPv6, source port number, destination port number, protocol number>+Flowlabel

Non-TCP/non-UDP

3-tuple <source IPv6, destination IPv6, protocol number>+Flowlabel

MPLS forwarding (P nodes in MPLS scenarios)

(MPLS->MPLS)

Number of Labels is not more than 5
  • If the IP header is next to MPLS label stack:
    • TCP/UDP: 5-tuple <source IP, destination IP, source port number, destination port number, protocol number>
    • Non-TCP/non-UDP: 3-tuple <source IP, destination IP, protocol number>
  • If the IP header is not next to MPLS label stack or there is no IP header: All labels
NOTE:

"The inner layer is the IP header" means that the MPLS label stack is followed by the IP header (for example, an MPLS L3VPN packet) or that only the L2 Ethernet header is carried between the MPLS label stack and IP header (for example, a VPLS packet). The inner layer is not the IP header in other cases, for example, when VLL is carried over MPLS and control word+Ethernet header+IP header is carried.

Number of Labels is more than 5

Five outer labels

VPLS forwarding on Ingress PE

(AC->MPLS)

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

Non-IP

2-tuple <source MAC, destination MAC>

EVPN forwarding on the ingress PE (AC->MPLS, AC->SRv6)

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

Non-IP

2-tuple <source MAC, destination MAC>

EVPN VWPS forwarding on the ingress PE (AC->MPLS, AC->SRv6)

IP carrying TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

IP carrying non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

Ethernet carrying non-IP

2-tuple <source MAC, destination MAC>

VLL forwarding on Ingress PE

(AC->MPLS)

IP carrying TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

IP carrying non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

Ethernet carrying non-IP

2-tuple <source MAC, destination MAC>

NOTE:

When traffic type is MPLS over Ethernet+non-IP, the hash factors vary according to the number of MPLS labels:

  • If the number of labels is 5 or less, the hash factors are the innermost label plus 12 bytes after the bottommost label. In this scenario, the same traffic may be hashed to multiple outbound interfaces, causing packet out-of-order. You are advised to run the load-balance hash-fields vll label-ip command to solve this problem.
  • If the number of labels is greater than 5, the hash factors are the five outermost labels.

Non-Ethernet carrying Non-IP

VC label.

IPv4 multicast

-

Not support hash

IPv6 multicast

-

Not support hash

NG-MVPN

-

Not support hash

Trunk Load Balance

Table 2 Default Hash Factors in Trunk Load Balance Scenario

Scenarios

Traffic Type

Default Hash Factors

L3 forwarding (including IPv4 L3VPN forwarding on Ingress PE)

IPv4 unicast

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

IPv6 unicast

TCP/UDP

5-tuple <source IPv6, destination IPv6, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IPv6, destination IPv6, protocol number>

MPLS forwarding

MPLS

Number of labels is not more than 5

  • If the IP header is next to MPLS label stack:

    - TCP/UDP: 5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

    - non-TCP/non-UDP: 3-tuple <source IP, destination IP, protocol number>

  • IP header is not next to MPLS label stack or there is no IP header: All labels
NOTE:

"The inner layer is the IP header" means that the MPLS label stack is followed by the IP header (for example, an MPLS L3VPN packet) or that only the L2 Ethernet header is carried between the MPLS label stack and IP header (for example, a VPLS packet). The inner layer is not the IP header in other cases, for example, when VLL is carried over MPLS and control word+Ethernet header+IP header is carried.

Number of labels is more than 5

Five outer labels

Bridged forwarding, and VPLS forwarding on PE (AC->MPLS or AC->AC)

IPv4

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

IPv6

TCP/UDP

5-tuple <source IPv6, destination IPv6, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IPv6, destination IPv6, protocol number>

MPLS

2-tuple <source MAC, destination MAC>

Non-MPLS and Non-IP

2-tuple <source MAC, destination MAC>

VPLS forwarding on egress PE (MPLS->AC)

Ethernet carrying IP

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

Ethernet carrying non-IP

2-tuple <source MAC, destination MAC>

VLL forwarding on ingress PE (AC->MPLS), VLL local connection (AC->AC)

IPv4

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

IPv6

TCP/UDP

5-tuple <source IPv6, destination IPv6, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IPv6, destination IPv6, protocol number>

Ethernet carrying MPLS

VC label

Ethernet carrying non-IP and non-MPLS

VC label

Non-Ethernet carrying non-IP

VC label.

VLL forwarding on egress PE (MPLS->AC)

IPv4/IPv6

TCP/UDP

5-tuple <source IP, destination IP, source port number, destination port number, protocol number>

Non-TCP/non-UDP

3-tuple <source IP, destination IP, protocol number>

Non-IP

VC label

IPv4 multicast

-

3-tuple <multicast source IP address, multicast group address, VPN instance>

IPv6 multicast

-

3-tuple <multicast source IP address, multicast group address, VPN instance>
Parent Topic: Load Balancing Description
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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