L******t
发帖数: 1985 | 1 On average for a mid/high-end router, how many nexthops (or adjacencies)
does it maintain to its immediate neighbors? A few hundreds? Or a few
thousand?
A BRAS can maintain a lot. But the focus here is on aggregate/core layer
router. A high # can be a major overhead. Just wanted some real case numbers
. Thanks for your input! |
I********x
发帖数: 858 | 2 I have never used more than four next hops for one prefix during my 15 year
networking experience.
numbers
【在 L******t 的大作中提到】
: On average for a mid/high-end router, how many nexthops (or adjacencies)
: does it maintain to its immediate neighbors? A few hundreds? Or a few
: thousand?
: A BRAS can maintain a lot. But the focus here is on aggregate/core layer
: router. A high # can be a major overhead. Just wanted some real case numbers
: . Thanks for your input!
|
L******t
发帖数: 1985 | 3 So realistically speaking, considering all physical interfaces and
subinterfaces, a router usually has no more than few hundreds nexthops (or
somewhat ARP/NDP entries) to maintain, correct? Network engineers just won't
do something beyond that.
year
【在 I********x 的大作中提到】
: I have never used more than four next hops for one prefix during my 15 year
: networking experience.
:
: numbers
|
I********x
发帖数: 858 | 4 Your question is not very clear. For same prefix normally there wont be many
different nexthop. But a router may have many different prefixes and each
prefix can have different next hop. For example, a Internet BGP router
should have more than 600k prefixes, but of course the next hop maybe same
for some of these prefix.
In old days, a ppp dialer router may have thousands of subscribers with
different next hop; now ethernet router can have 60k+ arp entries, depends
on the hardware.
't
【在 L******t 的大作中提到】
: So realistically speaking, considering all physical interfaces and
: subinterfaces, a router usually has no more than few hundreds nexthops (or
: somewhat ARP/NDP entries) to maintain, correct? Network engineers just won't
: do something beyond that.
:
: year
|
L******t
发帖数: 1985 | 5 Not talking about RIB/FIB prefixes. But direct neighbors equivalent to ARP/
NDP entries. Nexthop/Adjacency can mean remote peers. But here it only means
direct ones maintained at Layer 2.
Wanted to know the common practice. Sometimes QA simulate traffic from
thousands of directly connected hosts, which I do not think happens in any
real network.
many
【在 I********x 的大作中提到】
: Your question is not very clear. For same prefix normally there wont be many
: different nexthop. But a router may have many different prefixes and each
: prefix can have different next hop. For example, a Internet BGP router
: should have more than 600k prefixes, but of course the next hop maybe same
: for some of these prefix.
: In old days, a ppp dialer router may have thousands of subscribers with
: different next hop; now ethernet router can have 60k+ arp entries, depends
: on the hardware.
:
: 't
|
I********x
发帖数: 858 | 6 On one of my living router/switch, I have 11.5k arp entries. I have about 12
of these routers.
In my case these hosts are connected via tens of layer2 switches but routing
is done on this device.
means
【在 L******t 的大作中提到】
: Not talking about RIB/FIB prefixes. But direct neighbors equivalent to ARP/
: NDP entries. Nexthop/Adjacency can mean remote peers. But here it only means
: direct ones maintained at Layer 2.
: Wanted to know the common practice. Sometimes QA simulate traffic from
: thousands of directly connected hosts, which I do not think happens in any
: real network.
:
: many
|
