Cisco ASA имеет возможность одновременного подключения к двум провайдерам и автоматически переключать Default gateway между ними.
Возможностей тут конечно поменьше чем у IOS router, но функция вполне рабочая.

object network internal-pat-primary_obj
 nat (inside,outside1) dynamic interface
object network internal-pat-secondary_obj
 nat (inside,outside2) dynamic interface
!
sla monitor 1
 type echo protocol ipIcmpEcho 8.8.4.4 interface outside1
sla monitor schedule 1 life forever start-time now
!
track 1 rtr 1 reachability
!
route outside1 0.0.0.0 0.0.0.0 62.105.149.225 1 track 1
route outside2 0.0.0.0 0.0.0.0 200.112.100.137 100 

Конфиг полностью

: Saved
: Written by enable_15 at 09:51:44.667 UTC Tue Oct 7 2014
!
ASA Version 9.1(4)5 
!
hostname msk-asa-01
xlate per-session deny tcp any4 any4
xlate per-session deny tcp any4 any6
xlate per-session deny tcp any6 any4
xlate per-session deny tcp any6 any6
xlate per-session deny udp any4 any4 eq domain
xlate per-session deny udp any4 any6 eq domain
xlate per-session deny udp any6 any4 eq domain
xlate per-session deny udp any6 any6 eq domain
names
ip local pool vpnpool_pool 192.168.5.100-192.168.5.250 mask 255.255.255.0
!
interface Ethernet0/0
 nameif outside1
 security-level 0
 ip address 62.105.149.226 255.255.255.224 
!
interface Ethernet0/1
 shutdown
 no nameif
 no security-level
 no ip address
!
interface Ethernet0/2
 nameif outside2
 security-level 0
 ip address 200.112.100.138 255.255.255.252 
!
interface Ethernet0/3
 nameif inside
 security-level 100
 ip address 192.168.2.7 255.255.255.0 
!
interface Management0/0
 management-only
 shutdown
 nameif management
 security-level 100
 no ip address
!
boot system disk0:/asa914-5-k8.bin
ftp mode passive
same-security-traffic permit intra-interface
object network internal-pat-primary_obj
 subnet 192.168.0.0 255.255.0.0
object network internal-server-static_obj
 host 192.168.2.12
object network vpnpool_obj
 subnet 192.168.5.0 255.255.255.0
object network internal-pat-secondary_obj
 subnet 192.168.0.0 255.255.0.0
object-group network RFC1918_objg
 network-object 192.168.0.0 255.255.0.0
 network-object 172.16.0.0 255.240.0.0
 network-object 10.0.0.0 255.0.0.0
access-list outside_in extended permit icmp any any echo-reply 
access-list outside_in extended deny ip any any log 

access-list split-tunnel_acl standard permit 10.0.0.0 255.0.0.0 
access-list split-tunnel_acl standard deny host 192.168.1.4 
access-list split-tunnel_acl standard permit 192.168.0.0 255.255.0.0 
access-list split-tunnel_acl standard permit 172.16.0.0 255.240.0.0 

pager lines 24
logging enable
logging asdm informational
no logging message 106015
no logging message 313001
no logging message 313008
no logging message 106023
no logging message 710003
no logging message 106100
no logging message 302015
no logging message 302014
no logging message 302013
no logging message 302018
no logging message 302017
no logging message 302016
no logging message 302021
no logging message 302020
flow-export destination inside 192.168.2.49 9996
flow-export template timeout-rate 1
flow-export delay flow-create 60
mtu outside1 1500
mtu inside 1500
mtu management 1500
mtu outside2 1500
no failover
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-716.bin
no asdm history enable
arp timeout 14400
no arp permit-nonconnected
nat (inside,outside1) source static RFC1918_objg RFC1918_objg destination static vpnpool_obj vpnpool_obj no-proxy-arp route-lookup
!
object network internal-pat-primary_obj
 nat (inside,outside1) dynamic interface
object network internal-pat-secondary_obj
 nat (inside,outside2) dynamic interface
access-group outside_in in interface outside1
!
router ospf 10
 network 192.168.2.0 255.255.255.0 area 0
 log-adj-changes
 redistribute static subnets
!
route outside1 0.0.0.0 0.0.0.0 62.105.149.225 1 track 1
route outside2 0.0.0.0 0.0.0.0 200.112.100.137 100 
timeout xlate 3:00:00
timeout pat-xlate 0:00:30
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
timeout tcp-proxy-reassembly 0:01:00
timeout floating-conn 0:00:00
dynamic-access-policy-record DfltAccessPolicy
user-identity default-domain LOCAL
aaa authentication ssh console LOCAL 
aaa authentication http console LOCAL 
http server enable
http 192.168.1.0 255.255.255.0 management
http 192.168.2.0 255.255.255.0 inside
http redirect outside1 80
snmp-server host inside 192.168.2.49 community cmonitor
no snmp-server location
no snmp-server contact
snmp-server community cmonitor
snmp-server enable traps snmp authentication linkup linkdown coldstart warmstart
sla monitor 1
 type echo protocol ipIcmpEcho 8.8.4.4 interface outside1
sla monitor schedule 1 life forever start-time now
crypto ipsec security-association pmtu-aging infinite
crypto ca trustpool policy
!
track 1 rtr 1 reachability
telnet timeout 5
ssh 192.168.2.0 255.255.255.0 inside
ssh timeout 60
ssh key-exchange group dh-group1-sha1
console timeout 0
threat-detection basic-threat
threat-detection statistics
threat-detection statistics tcp-intercept rate-interval 30 burst-rate 400 average-rate 200
!
class-map global-class
 description flow-export-class
 match any
class-map inspection_default
 match default-inspection-traffic
!
!
policy-map type inspect dns preset_dns_map
 parameters
  message-length maximum client auto
  message-length maximum 512
policy-map global_policy
 class inspection_default
  inspect dns preset_dns_map 
  inspect ftp 
  inspect h323 h225 
  inspect h323 ras 
  inspect rsh 
  inspect rtsp 
  inspect esmtp 
  inspect sqlnet 
  inspect skinny  
  inspect sunrpc 
  inspect xdmcp 
  inspect sip  
  inspect netbios 
  inspect tftp 
  inspect ip-options 
 class global-class
  flow-export event-type all destination 192.168.2.49
 class class-default
  user-statistics accounting
!
service-policy global_policy global
prompt hostname context 
no call-home reporting anonymous
hpm topN enable
Cryptochecksum:2fd88b3cac6b909af6b51b0224ae7066
: end

Конфиг полностью

Проверка

show route
!
show sla monitor configuration
show sla monitor operational-state
!
show track 1
!
show xlate