Category Archives: reliability

from Huawei command line – “ping mac …, trace mac …”

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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. Continue reading

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VRRP on Huawei router

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Virtual Router Redundancy Protocol (VRRP) combines a group of routing devices on a LAN into a backup group that functions as a virtual router. From the host perspective in the LAN, it only needs the IP address of the virtual router rather than the IP address of a specific device in the backup group. Virtual IP address must be set as a default gateway for the host in the LAN. VRRP dynamically associates the virtual router with a physical device that transmits services. When the device fails, the second device is selected to handover traffic. The switchover should be transparent to users, allowing the internal and external networks to communicate without interruption. It, of course, depends on configured services. Most sensitive services need higher reliability and VRRP itself is not enough. But I will mention about it later in the post.

Let’s switch from theory to more practical things. Continue reading

BFD process-interface-status vs. process-pst

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BFD process-interface-status and process-pst are applicable only for single-hop BFD. Let’s assume that we have two routers directly connected through interface GE1/0/0.

process-interface-status

By associating BFD session status with interface status we can trigger fast route convergence. We can use this function only for BFD session that uses a default multicast IP address to detect the single-hop link. We can use association between BFD session status and interface status in the case, when transport devices exist on the link between the routers. As the actual physical path is segmented by transport devices, the routers on both ends need a long time to detect a fault that occurred on the link. The change of BFD status affects the protocol status of the interface and thus fast convergence is triggered. When the BFD session becomes DOWN, the correspondence interface status also goes to BFD_DOWN state, causing that this direct route is deleted from the routing table but the router can still forward BFD packets. Continue reading

huawei interface backup configuration

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There are two interface backup modes:

  1. Active/standby
  2. Load balancing

In common active/standby mode only one interface transmit services at any time. When active interface works properly, it transmit all the traffic. In case of fault of the primary interface, a backup interface with the highest priority starts transmitting packets. If primary interface recovers, traffic is switched back to active interface.

In load balancing mode, in case traffic volume exceeds an upper threshold set for active interface, a backup interface with the highest priority starts transmitting packets and load balancing is performed. Continue reading