{
    "@context": "https://schema.org",
    "@type": "DefinedTerm",
    "@id": "https://hostdir.net/glossary/route-reflector",
    "name": "Route Reflector",
    "description": "A BGP router that redistributes iBGP learned routes to other iBGP peers, breaking the requirement for a full mesh of iBGP sessions.",
    "url": "https://hostdir.net/glossary/route-reflector",
    "inDefinedTermSet": "https://hostdir.net/glossary",
    "termCode": "route-reflector",
    "mainEntityOfPage": "https://hostdir.net/glossary/route-reflector",
    "license": "https://creativecommons.org/licenses/by/4.0/",
    "_hostdir": {
        "kind": "glossary-term",
        "slug": "route-reflector",
        "canonical": "https://hostdir.net/glossary/route-reflector",
        "term": "Route Reflector",
        "category": "Networking & Routing",
        "category_slug": "networking-routing",
        "summary": "A BGP router that redistributes iBGP learned routes to other iBGP peers, breaking the requirement for a full mesh of iBGP sessions.",
        "definition": "A route reflector is a Border Gateway Protocol (BGP) router that relaxes the iBGP full-mesh rule. In standard iBGP, each router must peer with every other router in the same autonomous system (AS) to avoid routing loops. As the number of routers grows, this full mesh becomes impractical. A route reflector solves this by acting as a central hub. It accepts iBGP routes from its clients and reflects them to all other clients and non-client peers, while still applying the BGP path selection algorithm.\n\nThe route reflector uses three roles: client, non-client, and route reflector itself. Clients are iBGP speakers that peer only with the reflector. Non-clients are iBGP speakers that peer with the reflector but also maintain full mesh with other non-clients. The reflector propagates routes received from a client to all other clients and non-clients. Routes received from a non-client are sent only to clients. Routes received from an eBGP peer are sent to all clients and non-clients. To prevent loops, the reflector adds the originator ID and cluster list attributes. These attributes allow downstream routers to detect and discard routes that have already passed through the same cluster.\n\nRoute reflectors are widely deployed in large service provider and enterprise networks to scale iBGP. They are defined in RFC 4456, which obsoleted RFC 1966 and RFC 2796. A network can use multiple route reflectors for redundancy, often organized into clusters with a common cluster ID. Route reflectors do not modify the BGP next hop or AS path; they only change the route propagation rules. They are a fundamental tool for building scalable BGP networks without requiring a full iBGP mesh.",
        "examples": "An ISP has 50 routers in its backbone AS. Without a route reflector, each router would need 49 iBGP sessions, totaling 1,225 sessions. By deploying two route reflectors in separate clusters, each core router peers only with its local reflector, reducing the session count to roughly 100 sessions. The reflectors exchange routes between clusters, and all routers receive a full set of iBGP routes without a full mesh.",
        "key_facts": [
            "Eliminates the need for a full iBGP mesh by reflecting routes to clients.",
            "Defined in RFC 4456, which obsoleted RFC 1966 and RFC 2796.",
            "Uses originator ID and cluster list attributes to prevent routing loops.",
            "A route reflector can have multiple clients and multiple non-client peers.",
            "Multiple route reflectors can be deployed in the same AS for redundancy."
        ],
        "related_terms": [
            "BGP",
            "iBGP",
            "eBGP",
            "BGP Confederations",
            "Cluster ID",
            "Originator ID"
        ],
        "references": [
            {
                "title": "RFC 4456 - BGP Route Reflection: An Alternative to Full Mesh Internal BGP (IBGP)",
                "url": "https://datatracker.ietf.org/doc/html/rfc4456"
            },
            {
                "title": "BGP Route Reflection (Cisco Documentation)",
                "url": "https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-3s/irg-xe-3s-book/irg-bgp-route-reflector.pdf"
            }
        ],
        "word_count": 280,
        "license": "CC BY 4.0",
        "license_url": "https://creativecommons.org/licenses/by/4.0/",
        "attribution": "HostDir Glossary — https://hostdir.net/glossary/route-reflector"
    }
}