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assigning multiple IP addresses to network interface

Why might we want to assign multiple IP addresses to the same interface? The following are the most common scenarios:

  • hosts in the network segment use IP addresses on different networks
  • there are not enough host addresses on a logical network segment, suppose a /24 address space and 300 hosts
How to configure multiple IP addresses on Huawei devices?

Let’s configure a pair of routers connected via a Gigabit Ethernet link and use four different logical networks.

[labnarioR1]int gi 0/0/0
[labnarioR1-GigabitEthernet0/0/0]ip add 192.168.12.1 255.255.255.0
[labnarioR1-GigabitEthernet0/0/0]ip add 10.0.12.1 255.255.255.0 sub
[labnarioR1-GigabitEthernet0/0/0]ip add 10.0.22.1 255.255.255.0 sub
[labnarioR1-GigabitEthernet0/0/0]ip add 10.0.32.1 255.255.255.0 sub

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how to solve a problem of hanging alarms in Huawei U2000

Let’s assume that you have U2000 NMS server to monitor Huawei devices. We can manage these devices in 2 ways: outband or inband management. Outband management means that you have a separate DCN network to manage devices. It is commonly used for critical nodes, for example for backbone routers. Unlike to backbone network, it is difficult to implement DCN for mobile backhaul networks, where the number of devices reaches hundreds or even thousands. In such situation inband management is implemented to reduce cost. Then the decision how to send SNMP packets to the NMS server is based on routing protocols. The packets travel through the monitored network and are susceptible to all turbulences, which can appear in the network. This may lead to the fact that some SNMP packets may be lost by the network.

Let’s imagine such case. A link between a router and NMS is “DOWN”. No redundant link is established. The router sends SNMP trap to the NMS server but the server is not available. The SNMP packet is lost. Then the link is going to “UP” state and the router send SNMP trap to U2000. This trap is then dropped by U2000 because there is not related “DOWN” trap, which was lost before.

And what’s next?

U2000 synchronizes alarms with devices every 30 minutes and NMS server receives “DOWN” trap from the router, which was lost earlier. As the clearing trap was dropped, this “DOWN” alarm will not be cleared anymore. Then we have “DOWN” hanging (not cleared) alarm in U2000.

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console cable for Huawei ATN950B

Huawei ATN950B routers are designed and intended for Metropolitan Area Networks. They are relatively new devices and often used in IP RAN solutions for 2G, 3G and LTE.

But I would not like to describe this product. Let’s focus on console cable for ATN950B.

Let’s imagine you have such router, power it on and try to connect to console port. And … nothing …, no any prompt. A standard console cable, you used for NE40E or CX600, does not work.

Do not panic, do it yourself using standard console cable. How to do this? Look below:

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how to activate 10GE on CX600-X1-X2 platform

And after the holidays …

We can bring up a subject of 10GE interfaces on Huawei CX600-X1-X2 platform. The short subject but can be useful.

Let’s imagine that you have NPUI board installed on the router:

<CX600>display elabel 1

BoardType=CX67NPUI20
Item=03030MDQ
Description=CX600,CX67NPUI20,Network Processing Unit Integrated with 2-Port 10GBase LAN/WAN-XFP

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how to find “TTL exceeded” packets

Let’s imagine you are an IP engineer and suddenly found increasing number of “TTL exceeded” packets on your router. Your first thought is “what the hell is it? How to find a source of these packets?”

Take it easy. You will know how to investigate such issue on Huawei router.

[labnario]display ip statistics
  Input:     sum               2783201      local               2321967
             bad protocol            0      bad format                0
             bad checksum            0      bad options               0
             discard srr             0      TTL exceeded         494196
  Output:    forwarding              0      local                886008
             dropped                 0      no route                  0
  Fragment:  input                   0      output                    0
             dropped                 0
             fragmented              0      couldn't fragment         0
  Reassembling:sum                   0      timeouts                  0

As you can see there are “TTL exceeded” packets. “Display ip statistics” command shows packets that are directed to CPU. Don’t mix it up with packets found on the interface. For example, you don’t have dropped packets on the interface but “display ip statistics” shows such packets.

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