Ensuring Network Resilience: The Importance of Failover Testing for ISPs

-

 Objective: -

Failover testing is essential for ISPs to ensure service continuity, maintain customer satisfaction, and meet regulatory requirements. By regularly testing and refining failover mechanisms, ISPs can enhance the reliability and performance of their networks, ultimately leading to a more robust and trustworthy service for their customers.



                        Fig :1 Requirement of Failover test


1.Service Continuity

Less Downtime: Failover testing makes sure that if the main system fails, backup systems quickly take over, so there's minimal interruption for users.

Happy Customers: Reliable service means customers experience fewer disruptions, making them more likely to stay with the ISP.


2. Reliability and Redundancy

Backup Systems Work: Testing ensures that backup systems will effectively take over if the main system fails.

Network Stability: Regular testing helps the network handle problems without major issues.

 3. Performance and Load Balancing

Even Traffic Distribution: Failover systems balance the load across servers. Testing ensures this process works smoothly, even during failures.

Check Performance: ISPs can measure how well their systems perform during failovers and fix any problems.

4. Security and Compliance

 Follow Rules: Testing ensures the ISP meets regulatory requirements, avoiding fines.

 Protect Data: Failover systems help maintain security during attacks or failures, keeping customer data safe.

5. Operational Efficiency

Spot Issues Early: Regular testing identifies potential problems before they become serious.

Save Money: Preventing outages through effective failover testing saves the ISP money on emergency repairs and lost business.



Scenario-1   Rail wire ISP have 3 uplinks: Vodafone, Jio & GTPL. It should be fulfilled below condition:

1. If Vodafone & Jio link down, traffic should be automatically switch over on GTPL link.
2. If Jio & GTPL link down, Traffic should be automatically switch over on Vodafone link.
3. If Vodafone & GTPL link down, traffic should be automatically switch over on Jio link.
4. If one of the links down, traffic should be load-sharing in rest of both links.

Pre-requisite: -

1. To achieve failover test successfully, all prefixes should be advertised properly with 3 upstream provider ISP.
2. BGP received and advertised routes need to be checked properly at both ends router.
3. The no. of received and advertised routes should be same at all ends.
4. Generally, upload and download traffic takes priority wise ISP as per BGP attributes local-preference and AS-path respectively. 


               Fig :2 Architecture of Railwire network with upstream provider

CASE-1 Testing on GTPL link: -

◼ To test GTPL link, Tx team manually shutdown and Vodafone & Jio link, Traffic increases
gradually on Railwire_r1 <lag-1> GTPL_ r1 link from 11.92 % to 63.35 %.

◼ There is traffic dip observed due to link manually shutdown at Tx end towards Vodafone & Jio.

◼ Before start Activity: -


After manually shutdown at Tx end:-



CASE-2 Testing on Vodafone link:-

◼ To test Vodafone link, Tx team manually shutdown Jio and GTPL link, traffic on Railwire-r1<>Vodafone_r1 increases from 10.84 % to 38.4 % 

◼ There is traffic dip observed on Jio & GTPL link. Traffic automatically switches over Ralwire_r1 <> Vodafone_r1 link. 


CASE-3 Testing on Jio link:-

◼ To test Jio link, Tx team manually shutdown Vodafone and GTPL link, traffic on Railwire-r1<>Jio_r1 increases from 12.84 % to 39.5 % 

◼ There is traffic dip observed on Jio & GTPL link. Traffic automatically switches over Ralwire_r1 <> Jio_r1 link.

CASE-4 Testing for Load Sharing 

Tools to Monitor Load Sharing

Use these to see what happens during failover tests:

• NetFlow/IPFIX: To see traffic distribution.
• Telemetry or SNMP: To see link utilization.
• Ping/Traceroute: To see traffic paths.
• Traffic Generators: iPerf to simulate load for failover testing.
• Monitor Performance: Make sure backup links have enough bandwidth for failover traffic.
• Minimize Convergence Time: Tune routing protocol timers for faster failover.
• Verify Symmetry: Make sure bidirectional traffic flows are the same on both redundant paths.

Conclusion: -

A failover test checks if a network can switch traffic from a primary path, link or device to a backup in case of failure with minimal disruption. During the test one or more primary components (e.g. links, routers or paths) are intentionally disabled or degraded to see if the backup resources can handle the load. Key items to check are traffic redistribution, load sharing across redundant paths and metrics like convergence time and resource utilization. Proper failover testing involves simulating different failure scenarios, verifying policies (e.g. ECMP, MPLS-TE or SD-WAN rules) and looking at traffic patterns to ensure resilience and performance under failure.










Comments

Post a Comment

Popular posts from this blog

AI in NOC: A New Era for Capacity Planning and Network Management

-
Image
   Introduction :- Predicting router interface traffic in modern network management is critical to achieve optimal network performance, resource allocation, and proactively eliminate bottlenecks. This case study suggests using machine learning on network datasets to develop a model that predicts an actual router’s interface traffic versus an ideal router’s traffic. By evaluating historical data of network traffic and utilizing well-established machine learning API-based algorithms like Neural Networks, Decision Trees, and Ensemble Methods, this analysis reviews the formation possibilities of a strong prediction model with grand accuracy. At the end of the study, this paper reviews multiple factors and features related to the traffic in the interface such as the hour in the day, the day’s sequence in the week, the network protocol, the application, and the structure of the network. Additionally, it explores the machine learning algorithms to compare the accuracy of the ML model...
Read more

Basics of Multiprotocol Label Switching

-
Image
  Objective := Fast switching of packet. Load-balancing traffic. Segregation of traffic is possible customer wise in MPLS. MPLS as a 2.5 layer protocol :       MPLS works on VPN type technology.     It works on layer 2.5 OSI model.   0       MPLS header added and inserted between layer 2 (Data link layer) and layer 3 (Network layer) It   is also known as “shim” Protocol. Label : 20 bits label value is used and it takes any values from 0 to 1048575. Experimental : 3 bits used for experimental and it generally used for Qos Service. QoS Policy :- Stack :  I t’s 1 bit long . Either 0 or 1. TTL :  It’s size 8 bit long. It generally defined as how packet reach from source to destination. its value is decreased by one at each hop to prevent packet to get stuck in  network. RTT (Round trip time)  = RTL (Time require to reach packet from source to destination) + RTA  (Time require to reach packe...
Read more

Traffic engineering: An attractive feature of MPLS

-
Image
  MPLS  technology: - n   MPLS is working on “Push—Swap—POP” methodology. n   PUSH : iLER--- (ingress Label Edge router) – add Label at the edge of router. it is done by PE router. n   SWAP : Label swapping – Label is swapped between P routers. LSP (Label Switched Path) is used to forward packet from Source to destination.   Labels are Swapped between these P routers and built between border PE routers. n   POP : eLER--- (Egress Label Edge router) – it is used to remove label.   But sometimes label removal process is done before the edge of last PE router, last P router which is called as PHP (Penultimate HOP Popping). M PLS Label  Mechanism: - -           Basically, two labels are used in  MPLS.   1.       Transport label 2.       Service label   1.       Transport Label:-   ...
Read more