[c-nsp] Network design questions

[Ogaki, Hidenori]

Hi experts,

Since I am new with BGP/OSPF on Cisco product, your kind comment would
be highly appreciated.

Assuming a enterprise customer connecting to two IP-VPN with Carrier
A(Primary) and B(Backup).
CE-A and B is peering with each carrier(A/B)'s PE, where
C(Customer)-Router is using OSPF.

There are original and new plan. Though very long mail but only two
questions please below on new plan?



                                                  ## Site-1 ## ***
Site-B is also using the same diagram not shown here though.
                                                       |          
                                                +------C1------+
 redistribute bgp AAA metric 20 metric-type 1 < |              | >
redistribute bgp AAA metric 25 metric-type 1
                                              CE-A/1         CE-B/1  
redistribute ospf X match internal external 2 < |              | >
redistribute ospf X match internal external 2
                                                |              | >
AS-path prepend (+3)   
                       ## Site-2 ## CE-A/2---Carrier A     Carrier B
                                                                 IP-VPN
IP-VPN
                                                |              |
                                                |              |
                                              CE-A/H        CE-B/H
                        AS-path prepend (+1)  < |              | >
AS-path prepend (+2)
                                                +------CH------+
                                                        |
                                                 ## Site-Hub ##
## Original plan

- Carrier A is used as completely as primary, where Carrier B as
backup(normally no traffic going through)
- Site-1 and B(not shown though) is dual homing to both Carrier A and B.
- Site-2 is single homing to Carrier A.
- Site-Hub is dual homing to both Carrier A and B as Hub site, to secure
the traffic in case..
     1. CE-A/1 fails for the traffic between Site-1 and Site-2 via
Site-Hub through Carrier B.
     2. Carrier A whole down for the traffic between Site-1 and
Site-Hub.




                                                  ## Site-B ##
                                                       |          
                                                +------CB------+
 redistribute bgp AAA metric 25 metric-type 1 < |              | >
redistribute bgp AAA metric 20 metric-type 1
                                              CE-A/B         CE-B/B  
redistribute ospf X match internal external 2 < |              | >
redistribute ospf X match internal external 2
                         AS-path prepend (+3) < |              |   
                       ## Site-2 ## CE-A/2---Carrier A     Carrier B
                                                               IP-VPN
IP-VPN
                                                |              |
                                                |              |
                                              CE-A/H        CE-B/H
                        AS-path prepend (+1)  < |              | >
AS-path prepend (+2)
                                                +------CH------+
                                                        |
                                                 ## Site-Hub ##


## New plan

- Only the configuration change on Site-B since it decides to use
Carrier-B as Primary where Site-1 keep using Carrier-A as primary.
- Site-1 and B is dual homing to each Carrier A or B.
- Site-2 and 3 is single homing to Carrier A.
- Traffic between Site-B and Site-2 and 3 is via Site-Hub, it's accepted
by this customer but for me...
>>>>>>>>>>>>> Q1. Would someone let me now possible easiest way to route
the traffic from/to Site-2/3 is via Carrier A? where Site-B to Site Hub
is keep using Carrier B?
- Site-Hub is dual homing to both Carrier A and B as Hub site, to secure
the traffic in case..
     1. CE-A/1 fails for the traffic between Site-1 and Site-2 via
Site-Hub through Carrier B.
     2. Carrier A whole down for the traffic between Site-1 and
Site-Hub.
     3. CE-B/B fails for the traffic between Site-1 and Site-2 via
Site-Hub through Carrier A.
>>>>>>>>>>>>> Q2. Any other better way to route the traffic from/to
Site-B to/from Site-Hub only via Carrier B?

Cheers,
Hidenori