First of all, let's ditch the term "PPLB." The usual alternative to per packet load balancing (what's been being talked about here) is per prefix load balancing, which would also be "PPLB." The abbreviation is therefore more confusing than anything else.
Err. No, that would be worse. "Per prefix" load balancing is an artifact of the Cisco route cache. The route engine (ie the route table) isn't queried for every packet. Instead the route in the route cache is used. One doesn't configure "per prefix" load balancing. One configures load balancing, which adds multiple routes into the route table.
Modern Cisco routers do not use a "route cache", they use a fully populated forwarding table. And load balancing is automatic if you have several equal cost routes.
The route cache then causes only one of these routes to be used. On cisco, to enable PPLB, you turn off the route cache.
Many modern Cisco routers can perform per-packet load balancing without doing process switching (but this needs to be explicitly configured).
On Juniper, you configure it to put multiple routes in the route table. Its actaully more likely to happen on Junipers, because unless you configure additonal policies, you get load balancing on divergent links as well as non-divergent links. On
Modern Juniper routers cannot do per-packet load balancing *at all*. It is correct that the configuration statement says "per-packet", however it is really per-flow (and this is well documented). See for instance the description of Internet Processor II ASIC load balancing at http://www.juniper.net/techpubs/software/junos/junos70/swconfig70-policy/htm... I'm afraid your statements show a certain lack of knowledge about modern router architectures. Steinar Haug, Nethelp consulting, sthaug@nethelp.no