ONA Considerations

Review the following restrictions, limitations, and behavioral characteristics that are associated with the ONA.

ONA Network port requirements

The following are Network port mandatory requirements for configuring Fabric Extend on the VSP 4450 Series:

ONA Device port requirements

The following are Device port mandatory requirements for configuring Fabric Extend on the VSP 4450 Series:

Layer 3 and Layer 2 ONA requirements

An ONA is required for Fabric Extend Layer 3 core solutions. An ONA is not required in Layer 2 core solutions because the tunnels are point-to-point VLAN connections, not VXLAN. Therefore, there is no need for an ONA to encapsulate a VXLAN header to SPB packets.

DHCP server

ONAs require access to a local DHCP server to automatically configure IP addresses. Configure an untagged ONA management VLAN to where the ONA is connected with its network side interface. If DHCP is used, a DHCP relay configuration needs to be added to the ONA network side port in order for the ONA to get an IP address assigned from a DHCP server. Alternatively, you can manually configure its IP address and other required settings with the ONA Manual Configuration menu.

IP tunnel source address

Before the ONA can get an IP tunnel source address from the VSP 4450 Series, the following steps must be taken:

The syntax for the IP tunnel source address is: ip-tunnel-source-address <A.B.C.D> port <slot/port> [mtu <mtu_value>] [vrf WORD<1–16>].

Automatic routing of VXLAN packets on the VSP 4450 Series

If you configure an IP tunnel source address in a VRF instead of a GRT, then the VSP 4450 Series automatically routes VXLAN packets from the ONA network port into the VRF configured as part of the IP tunnel source. Although the ONA network port is a part of the management VLAN that is in the GRT, for VXLAN encapsulated packets, the VSP 4450 Series automatically routes the packets into the VRF in which the tunnel source IP address is configured. This is done using a filter rule that the VSP 4450 Series software automatically sets up that filters based on whether the incoming port is equal to the ONA network port and the packet has a VXLAN header.

The Management VLAN on the VSP 4450 Series that is used to communicate with the ONA must always be in a GRT and must not be a part of the IP tunnel source VRF.

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Autorouting between GRT and VRF

ONA Gateway

The ONA gateway has to be a local IP address on the ONA Management VLAN. The ONA gateway IP address must be the same as the local IP address of the VSP 4000 connected to the ONA.

Note

Note

Extreme does not support ONA gateway IP addresses that are not local to the VSP 4450 Series. For example, you cannot use a VRRP IP address configured in a switch cluster for the ONA gateway.

Maximum MTU

The ONA supports a maximum transmission unit (MTU) size of 1950 bytes. For the VSP 4450 Series to work with a switch that supports Fabric Extend natively, the MTU size must be left at the default setting of 1950. If the core network does not support jumbo frames, the VSP 4450 Series with ONA must be used on all sites.

Fragmentation and reassembly

If the maximum MTU size has to be fewer than 1594 bytes, then you require fragmentation and reassembly of packets. The VSP 4450 Series with ONAs support fragmentation and reassembly, but you must have VSP 4450 Series switches with ONAs at BOTH ends of the IP WAN connection.

QoS priority queues

The ONA 1101GT implements both Layer 2 and Layer 3 QoS. Specifically, it implements IEEE 802.1Q VLAN TCI PCP (Priority Code Point) and IETF IPv4 DSCP (Differentiated Services Code Point). These are implemented in hardware with the limitation that there are four Weighted Random Early Detection (WRED) priority queues, numbered 4 (highest) to 7 (lowest). The following tables show the mappings from the PCP and DSCP values in the packet to the priority queue.

The hardware puts each packet in 1 of the 4 HW queues in the following order:

  1. If a packet is a tagged VLAN packet, the PCP field determines the priority queue. (Ethertypes 0x8100 and 0x88a8 identify tagged VLAN packets.)

  2. If the packet is an IPv4 packet, the DSCP field determines the priority queue.

  3. Use the highest priority queue (4).

The HW QoS is always enabled, and the CP to priority queue mappings are static.

The following table defines the 3 bit VLAN PCP value to queue number mapping. The queues are numbered 4..7 with 4 being the highest priority and 7 the lowest priority.

Table 1. VLAN PCP to queue mapping

VLAN PCP

Queue Number

0

7

1

7

2

6

3

6

4

5

5

5

6

4

7

4

The following table defines the 6 bit IPv4 DSCP value to queue number mapping. The queues are numbered 4..7 with 4 being the highest priority and 7 the lowest.

Table 2. IPv4 DSCP to queue mapping

IPv4 DSCP

VLAN PCP

Queue Number

0

1

7

1

1

7

2

1

7

3

1

7

4

1

7

5

1

7

6

1

7

7

1

7

8

2

6

9

1

7

10

2

6

11

1

7

12

2

6

13

1

7

14

2

6

15

1

7

16

3

6

17

1

7

18

3

6

19

1

7

20

3

6

21

1

7

22

3

6

23

1

7

24

4

5

25

1

7

26

4

5

27

4

5

28

4

5

29

1

7

30

4

5

31

1

7

32

5

5

33

1

7

34

5

5

35

5

5

36

5

5

37

1

7

38

5

5

39

1

7

40

6

4

41

5

5

42

1

7

43

1

7

44

1

7

45

1

7

46

6

4

47

6

4

48

7

4

49

1

7

50

1

7

51

1

7

52

1

7

53

1

7

54

1

7

55

1

7

56

7

4

57

1

7

58

1

7

59

1

7

60

1

7

61

1

7

62

1

7

63

1

7