Friday , February 23 2024

fun with wildcard mask on Huawei device

You, as the network administrator, were tasked with providing access to a network, where 4 machines have been connected.

It is simple task. Nothing can happen, but…

Everything is ready and you are checking connectivity between RT2 and those machines, and… To your suprise, you can only ping even-numbered IP addresses:

[RT2]ping 192.168.10.1
   PING 192.168.10.1: 56  data bytes, press CTRL_C to break
     Request time out
     Request time out
     Request time out
     Request time out
     Request time out

 [RT2]ping 192.168.10.2
   PING 192.168.10.2: 56  data bytes, press CTRL_C to break
     Reply from 192.168.10.2: bytes=56 Sequence=1 ttl=127 time=30 ms
     Reply from 192.168.10.2: bytes=56 Sequence=2 ttl=127 time=20 ms
     Reply from 192.168.10.2: bytes=56 Sequence=3 ttl=127 time=30 ms
     Reply from 192.168.10.2: bytes=56 Sequence=4 ttl=127 time=40 ms
     Reply from 192.168.10.2: bytes=56 Sequence=5 ttl=127 time=30 ms

 [RT2]ping 192.168.10.3
   PING 192.168.10.3: 56  data bytes, press CTRL_C to break
     Request time out
     Request time out
     Request time out
     Request time out
     Request time out

 [RT2]ping 192.168.10.4
   PING 192.168.10.4: 56  data bytes, press CTRL_C to break
     Reply from 192.168.10.4: bytes=56 Sequence=1 ttl=127 time=30 ms
     Reply from 192.168.10.4: bytes=56 Sequence=2 ttl=127 time=40 ms
     Reply from 192.168.10.4: bytes=56 Sequence=3 ttl=127 time=30 ms
     Reply from 192.168.10.4: bytes=56 Sequence=4 ttl=127 time=30 ms
     Reply from 192.168.10.4: bytes=56 Sequence=5 ttl=127 time=30 ms

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QinQ termination on subinterfaces to support DHCP Relay

So far you have learned basic and selective QinQ on Huawei swiches. They seem like a simple Layer 2 VPN solution, which we can use to connect 2 or more offices. And of course, it is truth.

But, sometimes, we want to have an access to external services or just to the Internet, instead of connecting 2 branch offices. And, still we can use QinQ technology, why not?

The only thing we should do is to terminate QinQ VLAN Tag on a router. Just create L3 subinterface and let the router to use IP routing table to forward packets.

In our LAB, I am going to show you how to terminate QinQ to use DHCP server, located outside our network. In this case DHCP Relay feature must be used.

So let’s get to the point!

QinQ termination on subinterfaces to support DHCP Relay on Huawei

Topology of QinQ to support DHCP Relay

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selective QinQ on Huawei switches

Let’s go ahead with QinQ technology. In the last post you had the opportunity to know basic QinQ tunneling on Huawei switches. The QinQ tunnel attaches the same outer tag to all the frames entering the Layer 2 QinQ interface.

In this lab I would like to attach different outer tags, to the frames entering the Layer 2 QinQ interface, according to different inner tags. It is useful when packets are going to be differentiated in a provider’s network. Why? Because of service type, user’s application etc.

In this case we have 1 enterprise network with branch office located in another city. Customer network is divided into 2 VLANs to differentiate existing services. Our task is to transparently transmit packets, through ISP network, paying attantion to not allowing traffic between VLAN10 and VLAN20.

Selective QinQ topology

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