Thursday , May 24 2018

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.
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    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.

    Multicast

    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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    introduction to IPv6 – part 1

    To start using IPv6 in our labs, I decided to prepare a short introduction of it. As it is a broad topic I had to split it into several parts. Let’s start from the beginning.

    Short IPv6 history

    First IPv6 protocol specification was introduced in late 1995 in RFC1883, so it was 18 years ago! About one year later 6bone network was started as a virtual network over the IPv4-based Internet (using IPv6 over IPv4 tunneling). The mission of the 6bone was to establish the IPv6 environment for testing purposes.  In 1999 IPv6 Forum was founded and registries started assigning IPv6 prefixes to ISPs. In 2000, many vendors began to bundle IPv6 into their mainstream product lines. 2009 – first serious IPv4 address shortage in developed countries.

    What about IPv5?

    IPv5 was an experimental Resource Reservation Protocol, intended to provide QoS for multimedia and defined as the Internet Stream Protocol version 2 (ST2). It was designed to coexist with IPv4 and use the same addressing scheme, not as a replacement of IPv4. ST2 was designed to coexist with IPv4 on each node. The main role of the ST2 was to transfer a real-time multimedia, where IPv4 could be used for the transfer of traditional data and control information. ST2 is described in RFC1819.

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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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