Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 1
High-Availability Designs
for Junip...
2Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Routing and Firewall Functions Mergi...
3Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Routing and Firewall Functions Mergi...
4Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
JUNOS / ScreenOS Routing Strengths
V...
5Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
ScreenOS Dynamic Routing
ScreenOS is...
6Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
High Availability Scenarios
Firewall...
7Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Stateful Failover
True security boun...
8Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Classic Firewall HA Scenario
“Ten-Pa...
9Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Dynamic Routing / Firewall HA Scenar...
10Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Firewalls in a Dynamic Routing
Topo...
11Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NetScreen Redundancy Protocol
Origi...
12Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NSRP: Traditional (L3) Design
Virtu...
13Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NSRP: Traditional (L2) Design
Firew...
14Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Transparent Mode NSRP (L2) Operatio...
15Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NSRP Real-Time Object Sync
What is ...
16Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NSRP Operation
Master/Backup state ...
17Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NSRP State Control: Tracking
NSRP c...
18Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
OSPF and NSRP (The Wrong Way)
VERY ...
19Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Dynamic Routing Clusters
(1): Justi...
20Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Dynamic Routing Clusters (2): Opera...
21Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Primary limitations:
• VERY suscept...
22Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
HA Considerations: Stateful forward...
23Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
ScreenOS – Session State
All forwar...
24Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Asymmetric State: Symptoms
“Split-s...
25Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IGP Costing Exercise (1)
Predictabl...
26Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IGP Costing Exercise (2)
Predictabl...
27Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
IGP Costing Exercise (3)
IGP Costin...
28Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
NSRP: Data-Path Forwarding
NSRP can...
29Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Mixed-Mode NSRP (Simple)
Medium-siz...
30Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Mixed-Mode NSRP (VSD-less + DMZ)
Ad...
31Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Mixed-mode NSRP Complications
Must ...
32Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Questions?
33Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
Thank You
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Highavailability designs-for-juniper-netscreen-firewalls3740

  1. 1. Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net 1 High-Availability Designs for Juniper NetScreen Firewalls Dan Backman Senior Systems Engineer dbackman@juniper.net
  2. 2. 2Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Routing and Firewall Functions Merging New JUNOS Routing platforms (J / M) and AS PIC • Stateful firewall, IPsec and NAT services in JUNOS Expanded Routing functionality in NetScreen platforms New solutions possible: • Stateful Firewall, NAT, IPsec VPN termination and Dynamic Routing + !+ =
  3. 3. 3Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Routing and Firewall Functions Merging Traditional uses of dynamic routing in firewalls: • Dynamically advertise reachability of connected services • Statically routed VPNs advertised into IGP/iBGP • Dynamic path calculation • Firewalls participate in routing (usually RIP) • Limited control plane impacts • Relatively few prefixes • Limited policy/redistribution Today: • Deployments require: • Interchangable routing / firewall features • Juniper delivering integrated feature sets • AS PIC / J Series SFW/IPsec • Increasing routing functionality in ScreenOS
  4. 4. 4Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net JUNOS / ScreenOS Routing Strengths Virtualization • Native support for multiple routing tables • Multiple VRF and Logical routers in JUNOS • At least two Virtual Routerss in all ScreenOS platforms – Allows simple split tunneling at edge • Hundreds of VRs in NetScreen Systems • Multiple instances of routing protocols in JUNOS and ScreenOS Scalable, standards-based routing protocols (OSPF/BGP/RIPv2) PIM-SM and IGMP Proxy for dynamic multicast forwarding Dynamic route-based VPNs • Support for policy and route-based VPNs in ScreenOS and JUNOS
  5. 5. 5Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net ScreenOS Dynamic Routing ScreenOS is designed for integrated Firewall / Routing • Security platform from the ground-up • Integrated static and dynamic routing support • Multiple virtual IPv4 routing tables / Multiple routing instances Security Features • Screen function • DoS, IP spoofing, L3/L4 protocol anomaly detection • Flexible security zone model for all policy • Network interfaces bound to security zones • Sessions / flows bound to zones ,not interfaces • Allows real-time next-hop changes to existing flows • Critical to support dynamic routing in a firewall
  6. 6. 6Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net High Availability Scenarios Firewalls integral part of routing topology – need redundancy solutions • Border protection (Screen/Policy) • Inline to forwarding path at network border • Logical progression for integrated IDP – Add IDP into forwarding path with fewer headaches VPN Routing Edge • Redundant VPN termination at site • Stateful failover without dynamic routing impact
  7. 7. 7Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Stateful Failover True security boundaries require stateful inspection • Firewalls track individual network flows • Provide stateful enforcement of policies and DoS protection Redundancy requires stateful awareness • Firewall Cluster must support state synchronization Failover without state sync: • Results in loss of existing TCP/UDP sessions • Users must restart existing protocol connections Traditional firewall state sync does not account for dynamic routing
  8. 8. 8Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Classic Firewall HA Scenario “Ten-Pack” of routers, switches, firewalls, switches and routers • HSRP/VRRP/NSRP virtual addresses for next-hop • Static routing Pros: • Simple. No dynamic routing • No asymmetric state • Supports all firewall features/functions Cons: • May require redundant interfaces • No dynamic routing through firewalls • Requires additional devices (L2 switches) S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 HA Link UNTRUST TRUST Master Backup
  9. 9. 9Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Dynamic Routing / Firewall HA Scenario
  10. 10. 10Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Firewalls in a Dynamic Routing Topology: Why? Customer desire to integrate firewalls into existing network topology • Must support dynamic failover based on OSPF • Contiguous OSPF area • Full Link State in network edge • Advertise prefixes between internal network and external routers • Must support PIM-SM for multicast routing (ScreenOS 5.1) Interop eNet Design • NSRP VSD-less clusters originally designed for this topology 2 years ago
  11. 11. 11Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NetScreen Redundancy Protocol Originally designed to support stateful failover • Never intended to support asymmetric state VSD – Virtual Security Device • Logical failover domain within firewall • Master / Backup state machine per VSD VSI – Virtual Security Interface • Shared interface (Virtual IP/MAC pair) • Maps traffic into VSD RTO Mirror – Real Time Object Mirroring • State sync in NSRP cluster
  12. 12. 12Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NSRP: Traditional (L3) Design Virtual addressing • NSRP VSI and VRRP or HSRP on routers • All virtual MAC addresses as next-hop between routers and firewall cluster • Static routes throughout topology Single VSD for all traffic All firewall interfaces are virtual interfaces (VIP/MAC) • Easy to add additional zones/interfaces (DMZ) • No asymmetric state S T A T U S P O W E R 5 20 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 20 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 HA Link UNTRUST TRUST NSRP Backup NSRP Master VRRP Backup VRRP Master VRRP Backup VRRP Master Virtual Address Static Routes Virtual Address Default Route Virtual Address Static Routes Virtual Address Default Route
  13. 13. 13Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NSRP: Traditional (L2) Design Firewall operates as logical L2 learning bridge • Backup is in L2 blocking state • Must permit IGP adjacencies through firewall • No asymmetric state Topologies • Support for proprietary IGPs • “drop-in” / transparent firewalls S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2
  14. 14. 14Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Transparent Mode NSRP (L2) Operation Operate as logical L2 bridge • MAC learning and forwarding • Policy engine and forwarding still based on 5-tuple Must carefully engineer DMZ topology • ICMP redirect cannot force traffic across zone boundary Limited support for VLANs • VLAN tags preserved, but single inspection domain • No current support for VLAN tag rewrite • Enhancement coming in next major ScreenOS release
  15. 15. 15Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NSRP Real-Time Object Sync What is synchronized? • Sessions / IPsec SA / Crypto and VSD Configs • Master Backup replication in VSD • Bi-Directional replication in VSD-less cluster What is not synchronized? • Screens (pre-flow processing counters) • Application Level Gateways • TCP Setup / Inspection S T A T U S P O W E R 52 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 52 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 HA Link(s) UNTRUST TRUST NSRP Backup NSRP Master RTO Mirror Master Backup Normal Traffic Traffic on Failover
  16. 16. 16Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NSRP Operation Master/Backup state machine run per VSD • Priority and tracking (weight-based) determines master eligibility • Tracking: interface / IP reachability (ping) / Zone Master assumes virtual IP/MAC addresses for VSI • Physical interfaces in VSD 0 • Additional VSI (eg: eth2/1:1) Master synchronizes state to Backup device Backup blocks ports in L2/Transparent mode
  17. 17. 17Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NSRP State Control: Tracking NSRP can track various factors to determine master eligibility • Applies per VSD • Administrative weight per tracked object • Failover threshold per VSD Track: • Multiple IP addresses • Weight per address • Interfaces • Zones • Behaves like VLAN on L3 switch • any one interface with link == zone up
  18. 18. 18Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net OSPF and NSRP (The Wrong Way) VERY slow failover (40-60 sec) when using OSPF and NSRP Does support NSRP RTO mirror for session sync • NSRP backup has “down” interfaces in VSD id 0 • OSPF adjacency is “down” when in backup state • On failover: 1. Interface up 2. Reestablish OSPF adj. (must wait OSPF Dead Interval) 3. Database exchange 4. SPF calc 5. Populate routes • THEN, can begin forwarding traffic S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2
  19. 19. 19Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Dynamic Routing Clusters (1): Justification Desire to integrate firewall into IGP • Multiple egress paths, integrate into IGP routing • Control advertisement of default or external routes into IGP based on exterior connectivity • Continuity of IGP routing across firewalls • OSPF-based dynamic route selection • Simplified topology (no L2 switching required) ScreenOS modified (early 5.0x) to abstract sessions from interface to zone. • Allows route update to new next-hop without invalidating existing sessions New NSRP mode needed to keep routing adjacencies up
  20. 20. 20Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Dynamic Routing Clusters (2): Operation Dual Masters in VSD id 0 Bi-directional RTO mirroring between cluster members • All physical interfaces remain active and can support active routing protocol adjacencies • All devices in cluster can actively forward traffic Same as running OSPF on non-clustered devices, but adds session sync Config: • Must manually “unset vsd id 0” • “set nsrp rto-mirror session non-vsi”
  21. 21. 21Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Primary limitations: • VERY susceptible to asymmetric state issues • Require more complex config (mixed mode) for NAT support • Policy-based VPNs also require • In both cases, traffic must return to a single address which may be resident on both devices Cannot use Data-Path Forwarding as a band-aid • Both nodes are Master: only backup node can perform data-path forwarding Must use “Mixed-mode” NSRP to address these issues • Unset VSD id 0 • Virtual interfaces in VSD id 1 (loopback for VPN, NAT Pool) Dynamic Routing Clusters (3): Caveats
  22. 22. 22Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net HA Considerations: Stateful forwarding Real Stateful Inspection requires bidirectional forwarding • Traditional routing protocols do not guarantee symmetric bidirectional traffic flows • ECMP nearly guarantees asymmetric state • True stateful load balancing requires reverse hash for returning microflows • NetScreen firewalls use session/flow state for all forwarding paths • Required for stateful policy inspection • J/M/T/E series use stateless forwarding • LPM / J-Tree lookup per-packet on forwarding and firewall filters
  23. 23. 23Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net ScreenOS – Session State All forwarded traffic must have a session • Contains bidirectional flow information • Route lookup determines egress zone • Policy lookup from ingress to egress zone • NetScreen Systems forward traffic like L3/L4 switches 5200-17(M)-> get session slot 1: sw alloc 3/max 1000064, alloc failed 0, mcast alloc 0, di alloc failed 0 slot 2: hw0 alloc 1/max 1048576 slot 2: hw1 alloc 1/max 1048576 id 7267/s**,vsys 0,flag 00000040/0080/23,policy 320002,time 6, dip 0 11(0601):10.2.4.2/1->224.0.0.5/1,89,000000000000,15,vlan 0,tun 0,vsd 0,route 0 3(0010):10.2.4.2/1<-224.0.0.5/1,89,000000000000,4,vlan 0,tun 0,vsd 0,route 0 id 7268/s**,vsys 0,flag 00000040/0080/23,policy 320002,time 6, dip 0 7(0601):10.1.4.1/1->224.0.0.5/1,89,000000000000,14,vlan 0,tun 0,vsd 0,route 0 3(0010):10.1.4.1/1<-224.0.0.5/1,89,000000000000,4,vlan 0,tun 0,vsd 0,route 0 id 7269/s01,vsys 0,flag 10200440/0000/03,policy 1,time 1440, dip 0 11(0801):10.2.2.2/11033->10.1.255.1/23,6,00a0c96cce14,15,vlan 0,tun 0,vsd 0,route 74 7(4800):10.2.2.2/11033<-10.1.255.1/23,6,00a0c92490e4,14,vlan 0,tun 0,vsd 0,route 44 Total 3 sessions shown
  24. 24. 24Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Asymmetric State: Symptoms “Split-state” environment may appear to work in the lab • BUT: TCP handshake never completed through same device • Half-open sessions: User sees TCP sessions establish but freeze (short-lived TCP sessions) • Can “disable syn checking” but lose effective TCP inspection and protection • ALG cannot fully inspect control channels • Deep Inspection will fail • Integrated IDP will fail • “pinholes” may not open correctly • Some screening functions may depend on bidirectional traffic S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2
  25. 25. 25Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net IGP Costing Exercise (1) Predictable forwarding path • Ensure bidirectional path through firewalls • Must not allow transit through multiple firewalls • If ABRs directly connected to firewalls, make sure there is a valid Intra-Area route between ABRs in firewall area IGP costing is unidirectional • Must be careful to set IGP costing bidirectionally (must configure both sides of a link to the same cost) • Do NOT rely on automatic costing (varies between vendors and equipment types) S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2
  26. 26. 26Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net IGP Costing Exercise (2) Predictable failover • Control traffic paths in the event of a link-down event • This design preseves state through a firewall in a single link-break Fast IGP failover: • No split link • Can use aggregated interfaces between devices • Use /30 p2p links to skip dead timer / DR election on link-up S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2
  27. 27. 27Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net IGP Costing Exercise (3) IGP Costing Dangers: • Routed DMZ Network • Do not allow transit between firewalls • Carefully control costs within the OSPF area • Watch out for asymmetric costs • Use separate VR for DMZ network if necessary • Carefully test all iterations in a failover topology S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 External Router-A External Router-B Internal Router-A Internal Router-B DMZ Router
  28. 28. 28Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net NSRP: Data-Path Forwarding NSRP can correct asymmetric state in some situations • 2) BACKUP device receives packet that matches session from master • 3) packet is exception- forwarded (CPU forwarded) to master over HA link • 4) MASTER forwards packet to end node Do not rely on this behavior • Serious performance impact for large amounts of forwarded traffic S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2
  29. 29. 29Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Mixed-Mode NSRP (Simple) Medium-sized enterprise • Upstream OSPF to routers • Downstream (Trust) • Firewall cluster is first-hop router for internal network • Virtual IP/MAC in Trust VSI • VSI exported to OSPF Pro: • Simple integration of OSPF and Firewalls • No Asymmetric State Cons: • Requires both VSD-less (untrust) and VSD/VSI (trust) S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH A S E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 HA Link VSI: Shared Address OSPF (VSD-less) UNTRUST OSPF Area X TRUST (L2)
  30. 30. 30Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Mixed-Mode NSRP (VSD-less + DMZ) Add DMZ network to existing VSD-less NSRP cluster Pros: • Allows for DMZ network connected to OSPF meshed network Cons: • Must control asymmetric state with OSPF costing • Requires both VSD-less and VSD/VSI support S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 HA Link UNTRUST OSPF Area X TRUST OSPF Area X DMZ VSI OSPF Passive
  31. 31. 31Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Mixed-mode NSRP Complications Must link NSRP and OSPF failover in mixed mode • OSPF makes path calculations based on link state information from routers • NSRP elects master based on tracking information and priority • Unidirectional feedback • Add VSI as OSPF passive interface • Recommend adding NSRP zone tracking or IP ping tracking to control NSRP failover S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 S T A T U S P O W E R 5 2 0 0 C O M P A C T F L A S H 1T X / R XL I N K 1 0 / 1 0 0 A L A R MS T A T U SH AS E S S I O NF L A S H C O N S O L EM O D E M 5 0 0 0 - M G T 5 0 0 0 - 8 G 1 2 HA Link UNTRUST OSPF Area X TRUST OSPF Area X DMZ VSI OSPF Passive OSPF Trust-Untrust Transit Path VSD 1 Backup lo0 VSD 1 Master lo0 X OSPF Untrust-DMZ Transit Path NAT from loopback1:1
  32. 32. 32Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Questions?
  33. 33. 33Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net Thank You

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