Unequal cost load sharing

В случае использования нескольких каналов связи с одинаковой пропускной способностью, например, пары Е1, можно применить различные технологии, чтобы максимально эффективно использовать полученную полосу пропускания:
- MFR;
- MLPPP;
- Load Balancing с CEF, как per-destination sharing, так и per-packet sharing.

MFR и MLPPP можно использовать только на WAN-интерфейсах (v.35, g.703). Сейчас более распространены случаи, когда организуются резервные каналы связи меньшей пропускной способностью, чем у основного. Иногда ставится задача перенести часть нагрузки на резервный канал.
Возможные варианты:
- Балансировка средствами протокола EIGRP;
- Балансировка средствами MPLS TE.

В конфигурации, собранной на эмуляторе GNS3, используется два маршрутизатора, объединенных между собой парой интерфейсов. Признаюсь, что заметка в основном предназначена для хранения конфигураций.


Маршрутизатор 1:

Router#sh run
Building configuration...

Current configuration : 3831 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
ip cef
!
!
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
mpls traffic-eng tunnels
mpls traffic-eng link-management timers periodic-flooding 30
!
!
voice dsp waitstate 24898
!
!
!
!
!
!
!
!
!
!
!
!
!
archive
 log config
  hidekeys
!
!
!
!
!
!
class-map match-all ping
 match access-group name ping
!
!
policy-map ping
 class ping
    bandwidth 50
policy-map 150k
 class class-default
    shape average 150000
  service-policy ping
!
!
!
!
!
interface Loopback0
 ip address 10.0.0.1 255.255.255.255
!
interface Loopback1
 ip address 192.168.1.1 255.255.255.0
!
interface Tunnel0
 bandwidth 1000
 ip unnumbered Loopback0
 load-interval 30
 tunnel destination 10.0.0.2
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng autoroute announce
 tunnel mpls traffic-eng priority 7 7
 tunnel mpls traffic-eng bandwidth 100
 tunnel mpls traffic-eng path-option 1 explicit name SE1/0
 tunnel mpls traffic-eng path-option 2 dynamic
 tunnel mpls traffic-eng load-share 90
 service-policy output 150k
 no routing dynamic
!
interface Tunnel1
 ip unnumbered Loopback0
 load-interval 30
 tunnel destination 10.0.0.2
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng autoroute announce
 tunnel mpls traffic-eng priority 7 7
 tunnel mpls traffic-eng bandwidth 50
 tunnel mpls traffic-eng path-option 1 explicit name SE1/1
 tunnel mpls traffic-eng path-option 2 dynamic
 tunnel mpls traffic-eng load-share 30
 no routing dynamic
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex half
!
interface FastEthernet0/0.100
 encapsulation dot1Q 100
 ip address 10.2.2.0 255.255.255.254
!
interface Serial1/0
 bandwidth 100
 ip address 10.1.1.0 255.255.255.254
 ip router isis
 load-interval 30
 mpls traffic-eng tunnels
 mpls traffic-eng administrative-weight 100
 serial restart-delay 0
 max-reserved-bandwidth 100
 ip rsvp bandwidth 100
!
interface Serial1/1
 bandwidth 60
 ip address 10.1.1.2 255.255.255.254
 ip router isis
 load-interval 30
 mpls traffic-eng tunnels
 mpls traffic-eng administrative-weight 60
 serial restart-delay 0
 isis metric 20
 max-reserved-bandwidth 100
 ip rsvp bandwidth 60
!
interface Serial1/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/4
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/5
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/6
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/7
 no ip address
 shutdown
 serial restart-delay 0
!
router isis
 net 49.0000.0024.0000.0000.0001.00
 is-type level-2-only
 advertise passive-only
 metric-style wide
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
 passive-interface Loopback0
!
router bgp 65024
 template peer-session AS
  remote-as 65024
  update-source Loopback0
 exit-peer-session
 !
 no synchronization
 bgp log-neighbor-changes
 network 192.168.1.0
 neighbor 10.0.0.2 inherit peer-session AS
 no auto-summary
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
ip explicit-path name SE1/0 enable
 next-address 10.1.1.1
!
ip explicit-path name SE1/1 enable
 next-address 10.1.1.3
!
ip access-list extended ping
 permit icmp host 192.168.1.2 host 192.168.2.2
!
logging alarm informational
!
!
!
!
route-map aff permit 10
!
!
!
mpls ldp router-id Loopback0
!
control-plane
!
!
!
mgcp fax t38 ecm
mgcp behavior g729-variants static-pt
!
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 logging synchronous
 stopbits 1
line aux 0
 stopbits 1
line vty 0 4
 login
!
end

Router#

Маршрутизатор 2:

Building configuration...

Current configuration : 3458 bytes
!
upgrade fpd auto
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
ip source-route
ip cef
!
!
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
mpls traffic-eng tunnels
mpls traffic-eng link-management timers periodic-flooding 30
!
!
template peer-session
!
!
voice dsp waitstate 24898
!
!
!
!
!
!
!
!
!
!
!
!
!
archive
 log config
  hidekeys
!
!
!
!
!
!
!
!
!
interface Loopback0
 ip address 10.0.0.2 255.255.255.255
!
interface Loopback1
 ip address 192.168.2.1 255.255.255.0
!
interface Tunnel0
 ip unnumbered Loopback0
 load-interval 30
 tunnel destination 10.0.0.1
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng autoroute announce
 tunnel mpls traffic-eng priority 7 7
 tunnel mpls traffic-eng bandwidth 100
 tunnel mpls traffic-eng path-option 1 explicit name SE1/0
 tunnel mpls traffic-eng path-option 2 dynamic
 tunnel mpls traffic-eng load-share 90
 no routing dynamic
!
interface Tunnel1
 ip unnumbered Loopback0
 load-interval 30
 tunnel destination 10.0.0.1
 tunnel mode mpls traffic-eng
 tunnel mpls traffic-eng autoroute announce
 tunnel mpls traffic-eng priority 7 7
 tunnel mpls traffic-eng bandwidth 50
 tunnel mpls traffic-eng path-option 1 explicit name SE1/1
 tunnel mpls traffic-eng path-option 2 dynamic
 tunnel mpls traffic-eng load-share 30
 no routing dynamic
!
interface Tunnel9
 no ip address
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex half
!
interface Serial1/0
 bandwidth 128
 ip address 10.1.1.1 255.255.255.254
 ip router isis
 load-interval 30
 mpls traffic-eng tunnels
 mpls traffic-eng administrative-weight 100
 serial restart-delay 0
 max-reserved-bandwidth 100
 ip rsvp bandwidth 100
!
interface Serial1/1
 bandwidth 60
 ip address 10.1.1.3 255.255.255.254
 ip router isis
 load-interval 30
 mpls traffic-eng tunnels
 mpls traffic-eng administrative-weight 60
 serial restart-delay 0
 isis metric 20
 max-reserved-bandwidth 100
 ip rsvp bandwidth 60
!
interface Serial1/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/4
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/5
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/6
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/7
 no ip address
 shutdown
 serial restart-delay 0
!
router isis
 net 49.0000.0024.0000.0000.0002.00
 is-type level-2-only
 advertise passive-only
 metric-style wide
 mpls traffic-eng router-id Loopback0
 mpls traffic-eng level-2
 passive-interface Loopback0
!
router bgp 65024
 template peer-session AS
  remote-as 65024
  update-source Loopback0
 exit-peer-session
 !
 no synchronization
 bgp log-neighbor-changes
 network 192.168.2.0
 neighbor 10.0.0.1 inherit peer-session AS
 no auto-summary
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
ip explicit-path name SE1/0 enable
 next-address 10.1.1.0
!
ip explicit-path name SE1/1 enable
 next-address 10.1.1.2
!
logging alarm informational
!
!
!
!
!
!
mpls ldp router-id Loopback0
!
control-plane
!
!
!
mgcp fax t38 ecm
mgcp behavior g729-variants static-pt
!
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 logging synchronous
 stopbits 1
line aux 0
 stopbits 1
line vty 0 4
 login
!
end

Router#

В настройках туннелей включена опция load-sharing, что является по-сути per-packet sharing, но с учетом полосы. В примере это 3 к 1. Очевидно, что использовать подобную балансировку бессмысленно, если физические свойства каналов существенно отличаются.

Используемые материалы:
MPLS TE – Load Sharing
Perfect Load-Balancing: How Close Can You Get?