Labnario Huawei From Scratch

Let’s assume that we have a topology like in below picture:

1. AR1, AR2 and AR3 are in AS 100.
2. AR4 is in AS 200.
3. Loopback 100 of router AR1 and loopback 0 of router AR4 are advertised by BGP.

What we want to do is to configure default local preference attribute, which will determine the optimal route, for traffic that leaves AS 100. In our case, the whole traffic leaving AS 100 will go through AR3.

If a BGP device obtains multiple routes from different IBGP peers and these routes have different next hops to the same destination, the BGP device will select the route with the greatest Local_Pref value.

Huawei devices support generic MAC (GMAC) ping and trace on Layer 2 networks. Network administrators can use GMAC ping and trace functions to detect Layer 2 network faults, without configuring CFM.

ping mac mac-address vlan vlan-id [ interface interface-type interface-number | -c count | -s packetsize |-t timeout | -p priority-value ]

GMAC ping works at the same manner like 802.1ag MAC ping. It uses the Loopback Message and Loopback Reply (LBM/LBR) and is similar to ICMP ping function. GMAC ping can be used without configuring the MD (Maintenance Domain), MA (Maintenance Association), or MEP (Maintenance association End Point) on the source device, intermediate device, and destination device, as it is required when using 802.1ag. You only need to enable the GMAC function on the intermediate device. Therefore, GMAC ping is applicable to part of or a whole network without reference to MD, MA, and MEP configurations.

trace mac mac-address vlan vlan-id [ interface interface-type interface-number | -t timeout ] *

GMAC trace works at the same manner like 802.1ag MAC trace and uses Link Trace Message/Reply (LTR/LTM), so its function is similar to “trace route”. But GMAC trace can be implemented without configuring the MD, MA, or MEP on the source device, intermediate device, and the destination device. All the intermediate devices can respond with an LTR. Therefore, GMAC trace is applicable to part of or a whole network without reference to MD, MA, and MEP configurations.

1. CE1 and CE5 are in VPN labnario_1
2. CE2 and CE8 are in VPN labnario_2
3. ISIS level -2 as IGP
4. Connections CE1—PE3 and CE5—PE4 – static routes
5. Connection CE2—PE3 – OSPF
6. Connection CE8—PE4 – EBGP
7. Users in different VPNs cannot access each other.

A BGP/MPLS IP VPN uses the Border Gateway Protocol (BGP) to advertise VPN routes and the Multiprotocol Label Switching (MPLS) to forward VPN packets on backbone networks.

Some of you may know Cisco’s err-disable recovery feature, which allows to automatically bring a port from err-disable back to UP state. Huawei switches have similar functionality, which is called error-down auto-recovery.

There are five reasons a port can enter into error-down state:

• BPDU protection
• EFM threshold
• EFM remote failure
• Auto defend
• Link flapping
• MAC address flapping

Let’s take a look, how this feature works, in a network running STP, when BPDU protection is the reason that a port goes into DOWN state. If you are not familiar with BPDU protection feature, read my previous article “Protecting STP on Huawei switches”.

I have configured STP BPDU protection on the Ethernet 0/0/1 interface of labnarioSW1 switch as follows:

[labnarioSW1]int e0/0/1
[labnarioSW1-Ethernet0/0/1]stp edged-port enable
[labnarioSW1]stp bpdu-protection

Let’s check today how a Designated Intermediate System (DIS) is elected in broadcast network.

Unlike in OSPF, in ISIS, routers of the same level, in a network segment, set up adjacencies (including non-DIS routers). DIS, as a pseudo node also generates LSPs, to describe available routers in the network. A pseudo node is indentified by the system ID of the DIS and the 1-byte circuit ID, which is always not 0. The main task of DIS is to reduce the number of generated LSPs. Even though all routers set up adjacencies in an ISIS broadcast network, LSDBs are synchronized by the DISs. One router can be DIS either for Level -1 or Level 2 routers. It depends on DIS priority configured. You can configure different DIS priority for different levels. The highest priority means the router is elected as DIS. In case that all routers have the same DIS priority, the one with the highest MAC address is chosen as DIS. By default DIS priority is set to 64 and can be changed manually. Comparing to OSFP DR, the router with the priority 0 also takes part in DIS election. Each time you connect a new router with higher DIS priority, the new router is elected as the new DIS, which causes LSPs flooding.

Let’s leave theory and carry out a test of DIS election in ISIS broadcast network.

Based on the below topology configure, IP addresses for physical and loopback interfaces (it is omitted here).