Network load balancer it powerpoint presentation slides

So basically a Network Load Balancer spreads incoming traffic across multiple servers so none of them crash from being overloaded. It sits between users and your app servers, routing requests to healthy instances based on stuff like current load. Pretty much like a traffic cop (I know, weird analogy but it works). Health checks happen automatically too - if a server dies, traffic just goes to the others. You'll definitely need one if you're expecting traffic spikes or want high availability. Honestly saved my ass more than once when things got busy.

Oh right, so NLBs work at Layer 4 and ALBs at Layer 7. Basically NLBs just look at IP addresses and ports - they're crazy fast, like millions of requests per second fast. ALBs are way smarter though, they actually dig into your HTTP requests and can route based on URL paths, headers, that kind of stuff. Honestly I'd say NLBs are your speed demons when you need pure performance. ALBs shine when you need fancy routing logic. For simple TCP/UDP stuff, NLB's probably your best bet.

Honestly, you'd want a Network Load Balancer when you're dealing with insane traffic - like millions of requests per second. They work at Layer 4, so they're just looking at IP addresses and ports, not digging into the actual content. Super fast because of that. Perfect for TCP/UDP stuff, gaming servers, or IoT connections where every millisecond matters. Also preserves client IP addresses which can be clutch. I'd skip the ALB if you're not doing HTTP and latency is killing you. They're basically built for serious scale without the processing overhead.

So basically, network load balancers spread your traffic across multiple servers in different zones automatically. When one server dies (and it will happen), traffic just gets routed to the healthy ones - users don't even know anything went wrong. Health checks run constantly to catch issues early. Honestly the cross-zone thing is pretty clutch for avoiding outages. You can swap servers in and out for maintenance without any downtime too, which is nice. I'd set up at least 2-3 instances across different zones - that's where you'll really see the benefits kick in.

Monitor your active connections and new connections per second first - that shows your traffic patterns. Response time matters tons since slow pages kill user experience. Target health checks are honestly the most critical thing though, because unhealthy backends mean dropped requests. Track your throughput (bytes processed) and watch for connection errors too. Oh and definitely set up CloudWatch alarms for all this stuff. Trust me, you want alerts hitting your phone before customers start complaining about outages.

Honestly, I'd go with a Network Load Balancer if you need to scale fast without dealing with physical hardware nonsense. Hardware ones are solid until you max them out - then you're waiting weeks for new equipment while your site crashes. With NLBs you can handle crazy traffic spikes instantly, plus no upfront costs or maintenance headaches. They're perfect for unpredictable traffic or cloud apps. I mean, spinning one up takes literally minutes instead of calling vendors and waiting forever. If you're already on AWS and need to handle millions of requests, NLB is a no-brainer.

So NLBs do SSL termination but at the connection level, not application level like ALBs. Basically it decrypts your SSL/TLS traffic with your cert, then sends plain HTTP to your backend servers. Pretty nice since it takes that heavy encryption work off your servers. The cool part? You still get the original client IPs even after termination - which honestly beats ALBs for logging stuff. Oh and make sure your ACM certificate's set up right and your security groups allow both the encrypted and plain traffic ports. That part always trips people up.

So basically your NLB pings your backend servers constantly to see if they're actually alive and working. If one fails the health check, it just stops routing traffic there automatically - which is honestly pretty cool. You don't want users hitting broken endpoints, right? The trick is setting up a lightweight health check path that actually tests if your app works, not just whether the server boots up. I learned this the hard way when our health checks were too basic. You can tweak the intervals and what counts as "healthy" depending on your setup.

So basically, session persistence keeps users connected to the same backend server throughout their whole session instead of randomly jumping around. You set it up with sticky sessions - the load balancer just remembers which server handled someone's first request and keeps routing them there. Really matters for apps storing session data locally, like shopping carts or login info. Otherwise people lose everything mid-checkout, which honestly drives me crazy when it happens to me. You've got two main options: source IP persistence or application-controlled cookies, depending on what you're building.

So basically, load balancers sit between your users and servers, which hides your actual server IPs from attackers. They spread traffic around so no single server gets hammered during an attack. DDoS protection gets way easier too. Most of them work with services like CloudFlare or AWS Shield - honestly that combo is pretty solid. You can set rules to block sketchy traffic patterns or only allow certain sources. Oh, and you get one central spot to control everything instead of managing security on each server individually. Makes your whole setup way less exposed.

Health checks will drive you absolutely nuts if you're not careful. Too strict and they'll kill perfectly good instances, too loose and you're sending traffic to dead servers. SSL certs are annoying too - especially juggling multiple domains and staying on top of renewals. Oh, and connection draining during deployments trips up tons of people (learned that one the hard way). Definitely test your health check settings in staging first. Also keep a spreadsheet or something for cert expiration dates because getting paged at 2am for expired SSL is the worst.

Honestly, the algorithm makes or breaks your load balancing. Round Robin just goes server 1, 2, 3, repeat - works fine if all your servers are identical twins (spoiler: they're not). Least Connections is way smarter though. It sends new requests to whoever's got the least stuff going on right now. Your request processing times are gonna vary no matter what you do, so this handles real traffic much better. I'd go with Least Connections from the start. Round Robin feels like something from 2005 at this point.

So for NLB scaling, focus on target capacity and connection distribution first. Your backend servers need to actually handle the extra load - can't tell you how many times I've seen people forget that part lol. Cross-zone load balancing is worth considering if you're using multiple AZs, though it'll hit your costs a bit. Watch those target response times like a hawk during scaling. Honestly, start small and scale up gradually instead of going all-in right away. You'll catch bottlenecks way easier that way. Health check intervals matter too but they're not usually the main issue.

So basically you'd set your NLB as the origin for your CDN. Static stuff gets cached at edge locations, dynamic requests go back through the NLB to your servers. It's honestly a pretty solid setup - you get fast static content delivery plus high availability for the dynamic bits. CDN handles the caching while your load balancer keeps distributing traffic properly. Oh, and make sure those health checks are dialed in right or you'll end up routing to dead servers (learned that one the hard way). Works really well once it's running though.

NLBs are actually faster than other load balancers since they work at Layer 4 - just routing by IP and port without digging into packet contents. You're looking at single-digit millisecond latency, which honestly makes a huge difference for anything performance-critical. They can handle millions of requests per second too, so traffic spikes won't crush your users. The downside? You lose Layer 7 features like content-based routing, but that might not matter for your use case. I'd definitely track your response times before and after to see the actual improvement numbers.