Monday , January 22 2018

why does subinterface fail to forward packets

Let’s imagine that we have a simple topology like below:


Configure subinterfaces on both AR routers for VLAN tag termination:

[R1]interface GigabitEthernet 0/0/0.100
[R1-GigabitEthernet0/0/0.100]ip address 24
[R1-GigabitEthernet0/0/0.100]dot1q termination vid 100

[R2]int GigabitEthernet 0/0/0.100
[R2-GigabitEthernet0/0/0.100]ip address 24
[R2-GigabitEthernet0/0/0.100]dot1q termination vid 100

Try to ping IP address of neighboring router:

  PING 56  data bytes, press CTRL_C to break
    Request time out
    Request time out
    Request time out
    Request time out
    Request time out

  --- ping statistics ---
    5 packet(s) transmitted
    0 packet(s) received
    100.00% packet loss

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Huawei eNSP – news

And we have 2014 …

I hope you are doing well.

First of all, I’d like to thank you for your comments and suggestions. Not always I have time to respond for all your emails or comments but believe that all are appreciated. I maintain this blog after work but having 2 small absorbing children, it is not easy to reply for all your emails or even prepare a new post. I’ll do my best to publish new interesting and informative articles in the new year.

I believe that this year will be better for all of us.

So, let’s start 2014 with a new Huawei eNSP release:

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Huawei simulator eNSP – news

A new version of Huawei eNSP has been released.

What’s new in V100R001C00B210 version?

Based on a release notes for the newest eNSP:

  • Added IPSec protocol control plane to AR router.
  • Added SSLVPN feature to AR router.
  • Added function of sending UDP data stream to simulate PC
  • Added the function of capturing data on Cloud, FRS, HUB and PC.
  • Added a function of opening UDP ports of Cloud.
  • Improved functions of router’s AAA, DHCP and DNS.
  • Read More »

    hub&spoke in BGP/MPLS VPN

    Some time ago we talked about a basic configuration of BGP/MPLS VPNs. Let’s go on with hub&spoke networking today. Such solution can be adopted to control the mutual access of users, when an access control device is set. In this case no direct route exists between spoke sites. A spoke site advertises routes to a hub site and then the hub site advertises the routes to other spoke sites. Thus, communication between spoke sites is controlled by hub site.

    Let’s look at our topology:

    MPLS L3VPN hub and spoke topology

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    introduction to IPv6 – part 2

    Let’s keep going and finish IPv6 introduction.


    A multicast address identifies a group of interfaces. Traffic, that is sent to a multicast address, is sent to multiple destinations at the same time. An interface may belong to any number of multicast groups. Multicast addresses are defined by the prefix FF00::/8.

    The second octet defines the flags and the scope of the multicast address. Flags can be defined as:

    • 0 is reserved and must equal 0
    • R indicates rendezvous point and is almost always set to 0
    • P indicates prefix dependency and is almost always set to 0
    • T is the temporary bit. For a temporary multicast address T equals 1; for a permanent multicast address T equals 0.

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