Packet loss occurs when a router has to drop some packets because the buffer to store them is running out because the link where they are supposed to go is overloaded.
Bufferbloat is the issue where you make your queues too deep, i.e. you allocate too much RAM to buffering, while the cause of the buffering still exists, so the deeper queue just fills up anyway, so you haven’t improved anything, and have induced extra latency on the packets that do make it trough.
Deep buffers can help in situations where you have a step down in link speed, but only bursty and not sustained overloading of the slower output link.
The big bottleneck in router hardware is more about TCAM or HBM memory used to store the FIB of the global routing table. Since the table has grown so much the devices with less high speed memory can’t hold the table anymore, and if they start swapping the FIB to normal memory your routing performance goes to shit.
So not all of your concerns seem to apply to this class of device, but of course you’re right, The Register should have mentioned the RAM.
Thanks. You know a lot about hardware spec reqs in networking equipment. It always drives me crazy when buying a router because they dont seem to list this info.
Do you have any general advice for spec’ing hardware reqs for small businesses with event spaces with occasionally loads of people? How do u ensure the router can handle everyone’s traffic without dropping packets?
Packet loss occurs when a router has to drop some packets because the buffer to store them is running out because the link where they are supposed to go is overloaded.
Bufferbloat is the issue where you make your queues too deep, i.e. you allocate too much RAM to buffering, while the cause of the buffering still exists, so the deeper queue just fills up anyway, so you haven’t improved anything, and have induced extra latency on the packets that do make it trough.
Deep buffers can help in situations where you have a step down in link speed, but only bursty and not sustained overloading of the slower output link.
The big bottleneck in router hardware is more about TCAM or HBM memory used to store the FIB of the global routing table. Since the table has grown so much the devices with less high speed memory can’t hold the table anymore, and if they start swapping the FIB to normal memory your routing performance goes to shit.
So not all of your concerns seem to apply to this class of device, but of course you’re right, The Register should have mentioned the RAM.
Where do I find TCAM and HBM specs?
Thanks. You know a lot about hardware spec reqs in networking equipment. It always drives me crazy when buying a router because they dont seem to list this info.
Do you have any general advice for spec’ing hardware reqs for small businesses with event spaces with occasionally loads of people? How do u ensure the router can handle everyone’s traffic without dropping packets?
Wait, is this why packet shapers limiting bandwidth on one guest vlan drop so many damn packets? How do you prevent this?