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Module 30
Route Redistribution
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# ๐ CCNA 200-301 - Video 30: Route Redistribution ## Deep Study Notes --- ## ๐ Learning Objectives By the end of this video, you should understand: - What route redistribution is and why it's used - Redistribution between different routing protocols - Administrative Distance and its impact - Seed metrics and metric configuration - Redistribution issues and solutions - Route filtering and route maps --- ## ๐ง Core Concepts ### 1. What is Route Redistribution? **Definition:** Route redistribution is the process of taking routes learned from one routing protocol and injecting them into another routing protocol, allowing different routing domains to exchange routing information. **Analogy:** Think of route redistribution like a translator at the United Nations. Different countries (routing protocols) speak different languages. The translator (redistribution) converts information from one language to another so everyone can understand and communicate. ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ WHY REDISTRIBUTION IS NEEDED โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ Scenario: Company Merger โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ Company A (EIGRP) Company B (OSPF) โ โ โ โ โโโโโโโโโโโโโโโโโโโ โโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ โ โ โ โ โ โ 10.1.0.0/16 โ โ 172.16.0.0/16โ โ โ โ โ โ 10.2.0.0/16 โ โ 172.17.0.0/16โ โ โ โ โ โ โ โ โ โ โ โ โ โโโโโโโโโโฌโโโโโโโโโ โโโโโโโโโโฌโโโโโโโโโ โ โ โ โ โ โ โ โ โ โ โโโโโโโโโโโโโฌโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ โ โ โโโโโโโโผโโโโโโโ โ โ โ โ โ Router โ โ โ โ โ โ (Redistribute)โ โ โ โ โ โโโโโโโโโโโโโโโ โ โ โ โ โ โ โ โ Without Redistribution: A and B cannot reach each other's networks โ โ โ โ With Redistribution: A learns B's networks, B learns A's networks โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` --- ### 2. Redistribution Scenarios | Scenario | Description | Use Case | |----------|-------------|----------| | **Between Different Protocols** | OSPF โ EIGRP, OSPF โ RIP, etc. | Network mergers, migration | | **Between Same Protocol (Different AS)** | EIGRP 100 โ EIGRP 200 | Company divisions, design requirements | | **Static Routes into Dynamic Protocol** | Static โ OSPF/EIGRP | Connect to ISP, special networks | | **Connected Routes into Dynamic Protocol** | Directly connected โ OSPF/EIGRP | Advertise directly attached networks | ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ REDISTRIBUTION SCENARIOS โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ SCENARIO 1: OSPF โ EIGRP โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ OSPF Domain ASBR EIGRP Domain โ โ โ โ โโโโโโโโโโโ โโโโโโโ โโโโโโโโโโโ โ โ โ โ โ Area 0 โโโโโโโโโโ โโโโโโโโโโ AS 100 โ โ โ โ โ โโโโโโโโโโโ โโโโโโโ โโโโโโโโโโโ โ โ โ โ โ โ โ โ Redistribution: OSPF routes โ EIGRP, EIGRP routes โ OSPF โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ SCENARIO 2: EIGRP 100 โ EIGRP 200 โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ EIGRP 100 ASBR EIGRP 200 โ โ โ โ โโโโโโโโโโโ โโโโโโโ โโโโโโโโโโโ โ โ โ โ โ AS 100 โโโโโโโโโโ โโโโโโโโโโ AS 200 โ โ โ โ โ โโโโโโโโโโโ โโโโโโโ โโโโโโโโโโโ โ โ โ โ โ โ โ โ Redistribution: EIGRP 100 routes โ EIGRP 200 (and vice versa) โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ SCENARIO 3: Static โ OSPF โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ Static Route ASBR OSPF Domain โ โ โ โ โโโโโโโโโโโ โโโโโโโ โโโโโโโโโโโ โ โ โ โ โ ISP โโโโโโโโโโ โโโโโโโโโโ Area 0 โ โ โ โ โ โ Default โ โโโโโโโ โโโโโโโโโโโ โ โ โ โ โโโโโโโโโโโ โ โ โ โ โ โ โ โ Redistribution: Static default route โ OSPF โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` --- ### 3. Administrative Distance (AD) **Definition:** Administrative Distance is a measure of trustworthiness of a routing protocol. Lower AD = more trustworthy. ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ ADMINISTRATIVE DISTANCE VALUES โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ Route Source | Administrative Distance โ โ --------------------------------|----------------------------------------โ โ Connected Interface | 0 โ โ Static Route | 1 โ โ EIGRP Summary Route | 5 โ โ External BGP | 20 โ โ Internal EIGRP | 90 โ โ IGRP | 100 โ โ OSPF | 110 โ โ IS-IS | 115 โ โ RIP | 120 โ โ EGP | 140 โ โ External EIGRP | 170 โ โ Internal BGP | 200 โ โ Unknown | 255 (unusable) โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` **AD in Redistribution:** ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ AD IMPACT ON REDISTRIBUTION โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ When redistributing EIGRP into OSPF: โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ EIGRP routes (AD 90) โ become OSPF external routes (AD 110) โ โ โ โ โ โ โ โ Original route remains in routing table if AD is lower โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ When redistributing OSPF into EIGRP: โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ OSPF routes (AD 110) โ become EIGRP external routes (AD 170) โ โ โ โ โ โ โ โ Original route remains in routing table if AD is lower โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` --- ### 4. Seed Metrics **Definition:** When redistributing routes into a routing protocol, a "seed metric" must be assigned because the redistributed routes don't have native metrics for the new protocol. ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ DEFAULT SEED METRICS โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ Destination Protocol | Default Seed Metric โ โ -----------------------|--------------------------------------------------โ โ OSPF | 20 (except BGP routes = 1) โ โ EIGRP | None (must be configured) โ โ RIP | Infinity (16) - must be configured โ โ IS-IS | 0 (but may need configuration) โ โ BGP | IGP metric (or MED) โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` **Metric Configuration Examples:** ```cisco ! OSPF - default metric 20 (no configuration needed) Router(config)# router ospf 1 Router(config-router)# redistribute eigrp 100 ! EIGRP - must specify metric Router(config)# router eigrp 100 Router(config-router)# redistribute ospf 1 metric 10000 100 255 1 1500 ! metric = bandwidth, delay, reliability, load, MTU ! RIP - must specify metric Router(config)# router rip Router(config-router)# redistribute eigrp 100 metric 3 ! metric = hop count (1-16, 16 is unreachable) ``` --- ### 5. Redistribution Configuration **EIGRP โ OSPF:** ```cisco ! Configure OSPF to redistribute EIGRP routes Router(config)# router ospf 1 Router(config-router)# redistribute eigrp 100 subnets Router(config-router)# default-metric 30 Router(config-router)# exit ``` **OSPF โ EIGRP:** ```cisco ! Configure EIGRP to redistribute OSPF routes Router(config)# router eigrp 100 Router(config-router)# redistribute ospf 1 metric 10000 100 255 1 1500 Router(config-router)# exit ``` **RIP โ OSPF:** ```cisco ! Configure OSPF to redistribute RIP routes Router(config)# router ospf 1 Router(config-router)# redistribute rip subnets metric 30 Router(config-router)# exit ``` **Static โ OSPF:** ```cisco ! Configure OSPF to redistribute static routes Router(config)# router ospf 1 Router(config-router)# redistribute static subnets Router(config-router)# exit ``` **Connected โ EIGRP:** ```cisco ! Configure EIGRP to redistribute connected routes Router(config)# router eigrp 100 Router(config-router)# redistribute connected metric 10000 100 255 1 1500 Router(config-router)# exit ``` --- ### 6. Redistribution Metric Parameters **EIGRP Metric Parameters:** | Parameter | Description | Example | |-----------|-------------|---------| | **Bandwidth** | Minimum bandwidth in kbps | 10000 (10 Mbps) | | **Delay** | Delay in tens of microseconds | 100 (1000 ฮผs) | | **Reliability** | 1-255 (255 = 100% reliable) | 255 | | **Load** | 1-255 (1 = no load, 255 = 100% load) | 1 | | **MTU** | Maximum transmission unit | 1500 | ```cisco ! EIGRP metric syntax redistribute ospf 1 metric bandwidth delay reliability load MTU ! Example: 100 Mbps, 1 ms delay, full reliability, no load, 1500 MTU redistribute ospf 1 metric 100000 100 255 1 1500 ``` **OSPF Metric Parameters:** | Parameter | Description | |-----------|-------------| | **Metric** | OSPF cost (1-65535) | | **Metric-type** | 1 or 2 (E1 or E2) | | **Subnets** | Include subnets (required for classless) | ```cisco ! OSPF metric syntax redistribute eigrp 100 subnets metric 30 metric-type 1 ! OSPF metric examples redistribute eigrp 100 subnets ! default metric 20, type 2 redistribute eigrp 100 subnets metric 50 redistribute eigrp 100 subnets metric-type 1 ``` **RIP Metric Parameters:** | Parameter | Description | |-----------|-------------| | **Metric** | Hop count (1-15, 16 = unreachable) | ```cisco ! RIP metric syntax redistribute ospf 1 metric 3 ``` --- ### 7. Redistribution Issues and Solutions ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ REDISTRIBUTION ISSUES โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ ISSUE 1: Routing Loops โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ Router A โโโโโโโโโโโโโโโโโโ Router B โ โ โ โ โ โ โ โ โ โ โ Redistribution โ โ โ โ โ โ (Mutual) โ โ โ โ โ โ โ โ โ โ โ EIGRP Domain OSPF Domain โ โ โ โ โ โ โ โ Problem: Router A learns OSPF routes from Router B โ โ โ โ Router B learns EIGRP routes from Router A โ โ โ โ Routes may loop between protocols โ โ โ โ โ โ โ โ Solution: Route filtering, administrative distance manipulation โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ ISSUE 2: Suboptimal Routing โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ Network X (OSPF) โ โ โ โ โ โ โ โ โ Router A (OSPF) โโโโ Router B (ASBR) โโโโ Router C (EIGRP) โ โ โ โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ (Direct EIGRP) โ โ โ โ โ โ โ โ Problem: Router C may learn Network X via: โ โ โ โ โข Direct EIGRP from Router A (better path) โ โ โ โ โข OSPF โ EIGRP redistribution (worse path) โ โ โ โ Router chooses based on AD (90 vs 170) โ โ โ โ โ โ โ โ Solution: Adjust metrics or use route maps โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ ISSUE 3: Missing Subnets โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ Problem: OSPF redistribution without "subnets" keyword โ โ โ โ Only classful networks are redistributed โ โ โ โ โ โ โ โ Solution: Use "subnets" keyword โ โ โ โ redistribute eigrp 100 subnets โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ ISSUE 4: Inconsistent Metrics โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โ โ โ โ Problem: Routes redistributed with incorrect metrics โ โ โ โ May cause suboptimal routing or loops โ โ โ โ โ โ โ โ Solution: Configure appropriate metrics for redistribution โ โ โ โ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` --- ### 8. Route Maps for Redistribution **Definition:** Route maps are used to filter and modify routes during redistribution. They act like ACLs with more powerful actions. ``` โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ ROUTE MAP STRUCTURE โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโค โ โ โ route-map NAME permit|deny SEQUENCE_NUMBER โ โ match conditions โ โ set actions โ โ โ โ Example: โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ route-map REDISTRIBUTE permit 10 โ โ โ โ match ip address 10 โ โ โ โ set metric 100 โ โ โ โ โ โ โ โ route-map REDISTRIBUTE deny 20 โ โ โ โ match ip address 20 โ โ โ โ โ โ โ โ route-map REDISTRIBUTE permit 30 โ โ โ โ set metric 200 โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ โ โ โ โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ ``` **Match Conditions:** | Match Statement | Description | |-----------------|-------------| | `match ip address [acl]` | Match based on ACL | | `match ip next-hop [acl]` | Match based on next-hop | | `match interface [int]` | Match based on outgoing interface | | `match metric [value]` | Match based on metric | | `match route-type [type]` | Match based on route type | **Set Actions:** | Set Statement | Description | |---------------|-------------| | `set metric [value]` | Set metric for redistributed route | | `set metric-type [type]` | Set metric type (E1/E2 for OSPF) | | `set tag [value]` | Set tag for route | | `set level [level]` | Set IS-IS level | --- ### 9. Route Map Configuration Examples **Example 1: Redistribute Only Specific Networks** ```cisco ! Create ACL to match networks to redistribute access-list 10 permit 10.1.0.0 0.0.255.255 access-list 10 deny any ! Create route map route-map TO-OSPF permit 10 match ip address 10 ! Apply route map to redistribution router ospf 1 redistribute eigrp 100 route-map TO-OSPF subnets ``` **Example 2: Set Different Metrics for Different Routes** ```cisco ! Create ACLs access-list 10 permit 10.1.0.0 0.0.255.255 access-list 20 permit 10.2.0.0 0.0.255.255 ! Create route map with multiple sequences route-map SET-METRIC permit 10 match ip address 10 set metric 100 route-map SET-METRIC permit 20 match ip address 20 set metric 200 route-map SET-METRIC permit 30 set metric 300 ! Default for other routes ! Apply route map router eigrp 100 redistribute ospf 1 route-map SET-METRIC ``` **Example 3: Filter Routes Based on Next-Hop** ```cisco ! Create ACL for next-hop access-list 10 permit 192.168.1.1 access-list 10 permit 192.168.1.2 ! Create route map route-map FILTER-NH permit 10 match ip next-hop 10 set metric 100 ! Apply to redistribution router ospf 1 redistribute eigrp 100 route-map FILTER-NH subnets ``` --- ### 10. Preventing Redistribution Loops **Method 1: Administrative Distance Manipulation** ```cisco ! On ASBR, set AD for redistributed routes router eigrp 100 distance eigrp 90 150 ! Internal AD 90, External AD 150 router ospf 1 distance 110 ! Default AD ``` **Method 2: Route Tagging** ```cisco ! Tag routes when redistributing route-map TAG-OSPF permit 10 set tag 100 router ospf 1 redistribute eigrp 100 route-map TAG-OSPF subnets ! Filter tagged routes when redistributing back route-map FILTER-TAG deny 10 match tag 100 route-map FILTER-TAG permit 20 router eigrp 100 redistribute ospf 1 route-map FILTER-TAG ``` **Method 3: Route Filtering with ACLs** ```cisco ! Filter specific networks access-list 10 deny 10.0.0.0 0.255.255.255 access-list 10 permit any route-map FILTER-OSPF permit 10 match ip address 10 router eigrp 100 redistribute ospf 1 route-map FILTER-OSPF ``` --- ### 11. Redistribution Verification Commands | Command | Purpose | |---------|---------| | `show ip route` | View redistributed routes | | `show ip protocols` | View redistribution configuration | | `show ip route [network]` | View specific route details | | `show route-map` | Display route map configuration | | `debug ip routing` | Debug routing table updates | **Example Outputs:** ```cisco Router# show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 D EX 10.1.0.0/16 [170/28160] via 192.168.1.2, 00:01:23, GigabitEthernet0/0 D EX 10.2.0.0/16 [170/28160] via 192.168.1.2, 00:01:23, GigabitEthernet0/0 O E2 172.16.0.0/16 [110/20] via 192.168.1.1, 00:01:23, GigabitEthernet0/1 ``` ```cisco Router# show ip protocols Routing Protocol is "eigrp 100" Redistributing: ospf 1 Redistributing protocols: ospf 1 Redistributing: ospf 1 route-map REDISTRIBUTE Routing Protocol is "ospf 1" Redistributing: eigrp 100 Redistributing protocols: eigrp 100 Redistributing: eigrp 100 route-map FILTER ``` --- ## ๐ง Complete Configuration Examples ### Lab 1: OSPF โ EIGRP Mutual Redistribution **Topology:** ``` EIGRP Domain OSPF Domain (AS 100) (Area 0) โโโโโโโโโโโ โโโโโโโโโโโ โ Router Aโ โ Router Cโ โ 10.1.1.1โ โ 10.2.1.1โ โโโโโโฌโโโโโ โโโโโโฌโโโโโ โ โ โ โโโโโโโโโโโ โ โโโโโโโโโโโ Router Bโโโโโโโโโโโโ โ (ASBR) โ โโโโโโโโโโโ ``` **Router A (EIGRP Only):** ```cisco hostname RouterA ! interface GigabitEthernet0/0 ip address 10.1.1.1 255.255.255.0 no shutdown ! router eigrp 100 network 10.1.1.0 0.0.0.255 no auto-summary ! end ``` **Router B (ASBR - Redistribution):** ```cisco hostname RouterB ! interface GigabitEthernet0/0 ip address 10.1.1.2 255.255.255.0 no shutdown ! interface GigabitEthernet0/1 ip address 10.2.1.2 255.255.255.0 no shutdown ! ! EIGRP configuration router eigrp 100 network 10.1.1.0 0.0.0.255 no auto-summary ! ! OSPF configuration router ospf 1 network 10.2.1.0 0.0.0.255 area 0 ! ! Mutual redistribution router eigrp 100 redistribute ospf 1 metric 10000 100 255 1 1500 ! router ospf 1 redistribute eigrp 100 subnets metric 30 ! end ``` **Router C (OSPF Only):** ```cisco hostname RouterC ! interface GigabitEthernet0/0 ip address 10.2.1.1 255.255.255.0 no shutdown ! router ospf 1 network 10.2.1.0 0.0.0.255 area 0 ! end ``` --- ### Lab 2: Redistribution with Route Maps **Topology:** ``` EIGRP Domain OSPF Domain (AS 100) (Area 0) Networks: Networks: 10.1.0.0/16 172.16.0.0/16 10.2.0.0/16 172.17.0.0/16 192.168.1.0/24 ``` **ASBR Configuration with Route Maps:** ```cisco hostname ASBR ! ! Create ACLs for filtering access-list 10 permit 10.0.0.0 0.255.255.255 access-list 20 permit 192.168.1.0 0.0.0.255 ! ! Route map for EIGRP โ OSPF route-map EIGRP-TO-OSPF permit 10 match ip address 10 set metric 50 set metric-type type-1 ! route-map EIGRP-TO-OSPF deny 20 match ip address 20 ! route-map EIGRP-TO-OSPF permit 30 set metric 100 ! ! Route map for OSPF โ EIGRP route-map OSPF-TO-EIGRP permit 10 set metric 10000 100 255 1 1500 ! ! Redistribution with route maps router eigrp 100 redistribute ospf 1 route-map OSPF-TO-EIGRP ! router ospf 1 redistribute eigrp 100 route-map EIGRP-TO-OSPF subnets ! end ``` --- ### Lab 3: Preventing Redistribution Loops with Tags ```cisco hostname ASBR ! ! Create route map to tag OSPF routes route-map TAG-OSPF permit 10 set tag 100 ! ! Create route map to filter tagged routes route-map FILTER-TAGGED deny 10 match tag 100 ! route-map FILTER-TAGGED permit 20 ! ! Configure redistribution router eigrp 100 redistribute ospf 1 route-map FILTER-TAGGED metric 10000 100 255 1 1500 ! router ospf 1 redistribute eigrp 100 route-map TAG-OSPF subnets ! end ``` --- ## โ Exam Tips (For CCNA 200-301) | Topic | What Cisco Tests | |-------|------------------| | **Redistribution Purpose** | Connect different routing domains | | **AD Values** | EIGRP internal (90), OSPF (110), EIGRP external (170) | | **Seed Metrics** | OSPF (20), EIGRP (must specify), RIP (must specify) | | **Subnets Keyword** | Required for classless redistribution in OSPF | | **Route Maps** | Filtering and modifying redistributed routes | | **Mutual Redistribution** | Can cause loops; requires filtering | ### Common Exam Scenarios: **Scenario 1:** "EIGRP routes are redistributed into OSPF but only classful networks appear. What is missing?" - **Answer:** The `subnets` keyword in the redistribution command **Scenario 2:** "A router redistributes OSPF into EIGRP, but the routes do not appear in the EIGRP topology. What is likely the issue?" - **Answer:** Missing metric configuration for EIGRP redistribution **Scenario 3:** "Two routers perform mutual redistribution between OSPF and EIGRP. Routes start flapping. What is the likely cause?" - **Answer:** Redistribution loop; need route filtering or AD manipulation ### Mnemonics: **AD Values:** **"COED RIO" - Connected (0), OSPF (110), EIGRP (90), RIP (120)** - **C**onnected: 0 - **O**SPF: 110 - **E**IGRP Internal: 90 - **D** (EIGRP External): 170 - **R**IP: 120 **Redistribution Command:** **"RIP M, EIGRP M, OSPF M"** - **RIP**: Must specify metric (hop count) - **EIGRP**: Must specify metric (bandwidth, delay, reliability, load, MTU) - **OSPF**: Optional metric (default 20) --- ## ๐ Summary (1-Minute Revision) ``` ROUTE REDISTRIBUTION: PURPOSE: โโโ Exchange routes between different routing protocols โโโ Connect different network domains โโโ Enable communication across protocol boundaries ADMINISTRATIVE DISTANCE: โโโ Connected: 0 โโโ Static: 1 โโโ EIGRP Internal: 90 โโโ OSPF: 110 โโโ RIP: 120 โโโ EIGRP External: 170 SEED METRICS: โโโ OSPF: 20 (default) โโโ EIGRP: Must be configured โโโ RIP: Must be configured (1-15) โโโ BGP: IGP metric BASIC COMMANDS: โโโ redistribute eigrp 100 subnets (OSPF) โโโ redistribute ospf 1 metric 10000 100 255 1 1500 (EIGRP) โโโ redistribute rip metric 3 (OSPF) โโโ redistribute static subnets (OSPF) ROUTE MAPS: โโโ route-map NAME permit/deny SEQ โโโ match conditions (ip address, interface, metric) โโโ set actions (metric, metric-type, tag) โโโ Used for filtering and modification ISSUES: โโโ Routing loops (use tags, AD manipulation) โโโ Suboptimal routing (adjust metrics) โโโ Missing subnets (use "subnets" keyword) โโโ Metric inconsistency (configure seed metrics) VERIFICATION: โโโ show ip route โโโ show ip protocols โโโ show route-map โโโ debug ip routing ``` --- ## ๐งช Practice Questions **1. What is the default OSPF metric for redistributed routes?** - A) 1 - B) 10 - C) 20 - D) 100 <details> <summary>Answer</summary> <b>C) 20</b> - OSPF assigns a default metric of 20 to redistributed routes (except BGP routes which get 1). </details> **2. Which keyword is required when redistributing into OSPF to include subnets?** - A) `classless` - B) `subnets` - C) `detailed` - D) `all` <details> <summary>Answer</summary> <b>B) `subnets`</b> - Without the `subnets` keyword, only classful networks are redistributed. </details> **3. What is the administrative distance of OSPF?** - A) 90 - B) 110 - C) 120 - D) 170 <details> <summary>Answer</summary> <b>B) 110</b> - OSPF has an AD of 110. </details> **4. Which command redistributes EIGRP into OSPF?** - A) `redistribute eigrp 100` - B) `redistribute eigrp 100 subnets` - C) `redistribute eigrp 100 metric 20` - D) `redistribute eigrp 100 area 0` <details> <summary>Answer</summary> <b>B) `redistribute eigrp 100 subnets`</b> - This redistributes EIGRP routes into OSPF with subnet information. </details> **5. What is the administrative distance of EIGRP external routes?** - A) 90 - B) 110 - C) 170 - D) 200 <details> <summary>Answer</summary> <b>C) 170</b> - EIGRP external routes have AD 170. </details> **6. Which command redistributes OSPF into EIGRP with specific metric?** - A) `redistribute ospf 1` - B) `redistribute ospf 1 metric 20` - C) `redistribute ospf 1 metric 10000 100 255 1 1500` - D) `redistribute ospf 1 subnets` <details> <summary>Answer</summary> <b>C) `redistribute ospf 1 metric 10000 100 255 1 1500`</b> - EIGRP requires bandwidth, delay, reliability, load, and MTU. </details> **7. What is the purpose of a route map in redistribution?** - A) Filter and modify routes - B) Enable routing protocol - C) Configure interfaces - D) Set IP addresses <details> <summary>Answer</summary> <b>A) Filter and modify routes</b> - Route maps allow selective redistribution and metric modification. </details> **8. Which command prevents redistribution loops by tagging routes?** - A) `set tag 100` - B) `match tag 100` - C) `set metric 100` - D) `match metric 100` <details> <summary>Answer</summary> <b>A) `set tag 100`</b> - Tags can be set on redistributed routes and filtered to prevent loops. </details> **9. What is the default EIGRP external AD?** - A) 90 - B) 110 - C) 170 - D) 200 <details> <summary>Answer</summary> <b>C) 170</b> - EIGRP external routes have AD 170. </details> **10. Which command shows redistribution configuration?** - A) `show ip route` - B) `show ip protocols` - C) `show ip eigrp neighbors` - D) `show running-config` <details> <summary>Answer</summary> <b>B) `show ip protocols`</b> - Displays redistribution information and route maps. </details> **11. What is the default RIP metric for redistributed routes?** - A) 0 - B) 1 - C) 15 - D) 16 (unreachable) <details> <summary>Answer</summary> <b>D) 16 (unreachable)</b> - RIP requires a metric to be specified; default is infinity. </details> **12. Which command redistributes static routes into OSPF?** - A) `redistribute static` - B) `redistribute static subnets` - C) `redistribute static metric 20` - D) `redistribute static route-map` <details> <summary>Answer</summary> <b>B) `redistribute static subnets`</b> - This redistributes static routes with subnet information. </details> --- ## ๐ Next Steps After completing Video 30, you should be ready for: - **Video 31:** WAN Technologies - **Video 32:** PPP and HDLC **Lab Practice:** 1. Configure OSPF and EIGRP on separate routers 2. Configure mutual redistribution on ASBR 3. Verify redistributed routes with `show ip route` 4. Configure route maps to filter specific networks 5. Configure route maps to modify metrics 6. Use route tags to prevent redistribution loops --- **Ready for Video 31?** Share the link or say "next" and I'll continue with WAN Technologies. I'll continue with **Video 31: WAN Technologies** based on the standard CCNA 200-301 curriculum. ---