[iproute2] iproute2 question

[iproute2] iproute2 question

[thomas yang]

Hi,

Linux router R (has some interfaces)  use the table "main" as default
routing table to route packets.  If  some link connected to R failed,
I want to use another table "backup_tbl" to route packets; if the
broken link repaired , go back to use table "main"  .  How to do this?

Re: [iproute2] iproute2 question

[Stephen Hemminger]

On Thu, 18 Mar 2010 17:02:16 +0800
thomas yang <lampsu@gmail.com> wrote:

> Hi,
> 
> Linux router R (has some interfaces)  use the table "main" as default
> routing table to route packets.  If  some link connected to R failed,
> I want to use another table "backup_tbl" to route packets; if the
> broken link repaired , go back to use table "main"  .  How to do this?

That's now it works. Use a real routing daemon.

-- 

Re: [iproute2] iproute2 question

[thomas yang]

2010/3/18 Stephen Hemminger <shemminger@vyatta.com>:
> On Thu, 18 Mar 2010 17:02:16 +0800
> thomas yang <lampsu@gmail.com> wrote:
>
>> Hi,
>>
>> Linux router R (has some interfaces)  use the table "main" as default
>> routing table to route packets.  If  some link connected to R failed,
>> I want to use another table "backup_tbl" to route packets; if the
>> broken link repaired , go back to use table "main"  .  How to do this?
>
> That's now it works. Use a real routing daemon.
>

I want to reduce the packet loss that happens while routers converge
after a topology change due to a failure, use precalculated backup
table to do rapid failure repair  (repair faster than routing daemon,
fast reroute).
I do static routing on my linux routers.  When  some link  failed,
 I want to  use backup tables to route packets.  Can iproute2 do this?

Re: [iproute2] iproute2 question

[Stephen Hemminger]

On Fri, 19 Mar 2010 13:53:23 +0800
thomas yang <lampsu@gmail.com> wrote:

> 2010/3/18 Stephen Hemminger <shemminger@vyatta.com>:
> > On Thu, 18 Mar 2010 17:02:16 +0800
> > thomas yang <lampsu@gmail.com> wrote:
> >
> >> Hi,
> >>
> >> Linux router R (has some interfaces)  use the table "main" as default
> >> routing table to route packets.  If  some link connected to R failed,
> >> I want to use another table "backup_tbl" to route packets; if the
> >> broken link repaired , go back to use table "main"  .  How to do this?
> >
> > That's now it works. Use a real routing daemon.
> >
> 
> I want to reduce the packet loss that happens while routers converge
> after a topology change due to a failure, use precalculated backup
> table to do rapid failure repair  (repair faster than routing daemon,
> fast reroute).
> I do static routing on my linux routers.  When  some link  failed,
>  I want to  use backup tables to route packets.  Can iproute2 do this?

You could probably kludge something with multiple route tables
and modifying a single 'ip rule'.
Something like:
   http://www.linuxhorizon.ro/iproute2.html

[iproute2] iproute2 question

[thomas yang]

>>
>> I want to reduce the packet loss that happens while routers converge
>> after a topology change due to a failure, use precalculated backup
>> table to do rapid failure repair  (repair faster than routing daemon,
>> fast reroute).
>> I do static routing on my linux routers.  When  some link  failed,
>>  I want to  use backup tables to route packets.  Can iproute2 do this?
>
> You could probably kludge something with multiple route tables
> and modifying a single 'ip rule'.
> Something like:
>   http://www.linuxhorizon.ro/iproute2.html
>

I want to use different routing tables  with different  TOS (or DSCP)
e.g.
iptables -t mangle -A PREROUTING -j TOS --set-tos 0x10
...
then,
ip rule add tos 0x10 table 100
ip rule add tos 0x08 table 200
...
but there are only five TOS values  0x00,0x02,0x04,0x08,0x10. I need
more TOS values.

Does cmd 'ip rule' support DSCP ? (e.g. 'ip rule add dscp 0x11 tables 10')