[c-nsp] The Different between Cisco & Juniper (Technically)

[Gert Doering]

Hi,

On Sat, Oct 08, 2005 at 01:34:55AM +0200, Mounir Mohamed wrote:
> I didn't get chance to configure or working with Juniper routers so please I
> need to know what is the different (Technically) between Juniper and Cisco
> routers

<political>
There's no difference.  Both companies started building great devices,
and eventually lost track of customer demands and started orienting towards
"how to earn the most money".  Just the time frame is different, Cisco
is already orienting back towards their customers, while Juniper is still
looking for the money.
</political>


For a technical explanation: this is near to impossible in a few lines,
as there is no "the Cisco router", to start with - low-end Cisco boxes
use a single CPU for all work they do (routing protocols and packet
forwarding), high-end Ciscos are partially or fully distributed, using
the CPU only for routing protocols, and all packet forwarding is done
on autonomous line cards, with lots of hardware support for fast packet
forwarding.


Juniper had, for the longest time, only distributed platforms (M5, M10,
...) where a hardware forwarding plane cared for moving packets in high
speed, not affected by CPU cycles spent on routing protocols, while a 
dedicated routing engine (a modified i386 PC with a modified FreeBSD 
on it) did all the routing protocol work.  Recently, they have started
building PC-hardware-based low-end routers that do "all on a single CPU",
but they have built a real-time microkernel "below" the FreeBSD OS used
for the routing engine, and the microkernel does the packet forwarding,
simulating the hardware forwarding engine of the bigger boxes.


>From a user perspective, Juniper used to stand for reliable high-speed
packet forwarding with somewhat reduced feature sets - everything that
cannot be done in full speed in hardware isn't done at all.  Cisco on
the other end used to stand for maximum flexibility and features, but
some of those with really bad performance, and lots of bugs in 
confusing IOS versions.  But this is also changing with IOS XR, ION, 
and the new hardware platforms - "fast but reduced feature set"
describes both the 7600, (current) GSR and CRS-1 pretty well... - and
on the other hand, Juniper is adding things like NAT...

Whether "more features" or "all in hardware" is more important of course
depends very much on what you are going to do with the box.


>From a customer perspective (customer of an ISP that is using J or C
routers) there should not be a significant difference, if the ISP knows
what they are doing.


Overall, "Cisco vs. Juniper" is a very religious debate, and I'm certainly
going to be flamed for getting some details wrong, or for being biased :-)

gert

-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de